Enrich. Currency. he symbol,, is used to indicate the euro. he exchange rate between dollars and euros changes very day. $1.00 is worth about 0.70.

Transcription

1 Enrich Currency he currency used in the United States is the US dollar. Each ollar is divided into 100 cents. Most countries have their own urrencies. Most countries in Europe use a common monetary nit that is called the euro. he symbol,, is used to indicate the euro. he exchange rate between dollars and euros changes very day. $1.00 is worth about dd or subtract to solve each problem.. Henry bought a pair of shoes for and a pair of pants for How much money did he spend? Louis receives a week for doing his chores. His sister is younger and has fewer chores. She receives How much money do Louis and his sister receive together in one week? A gallon of Brand A of vanilla ice cream costs A gallon of Brand B vanilla ice cream costs How much money will Luca save if he buys Brand A instead of Brand B? Michael passed up a pair of jeans that cost and decided to buy a pair that were only How much money did he save by buying the less expensive jeans? Jesse s favorite magazine costs 1.75 at the store. If he buys a subscription, each issue is only How much money will Jesse save on each issue if he buys a subscription? Layla wants to buy a CD for and a book for She has How much more money does she need to buy the CD and book? Lynne s lunch came to Her drink was How much did she spend total? What would be the equivalent dollar amount? 5.50; $7.86. At the grocery store, Jaden purchased a box of cereal for $3.55 and a gallon of milk for $2.89. He gave the cashier $ How much change did he receive? What would be the equivalent euro amount? $3.56; Course 1 Chapter 3 Compute with and Multi-Digit Numbers

2 NAME DATE PERIOD Lesson 1 Extra Practice Add and Subtract Decimals Find each sum Find each difference Course 1 Chapter 3 Compute with Multi-Digit Numbers

3 Lesson 1 Homework Practice Add and Subtract Decimals Find each sum or difference SHOPPING Lorena bought groceries for $ and new shoes for $ How much did Lorena spend on groceries and shoes altogether? 14. SCHOOL The school is 3.2 blocks from Hector s house. How many blocks does Hector walk to go to and from school? 15. FOOD Jabir buys 2.74 pounds of dried pinto beans and 4.05 pounds of dried lima beans. What is the difference between the weights of the beans that Jabir buys? 16. WEIGHT Kelly s baby brother weighs 7.71 pounds. Her newborn kitten weighs 0.24 pound. How much more does Kelly s baby brother weigh than her kitten? Course 1 Chapter 3 Compute with Multi-Digit Numbers 35

4 Lesson 1 Problem-Solving Practice Add and Subtract Decimals Solve. 1. MONEY Last month, Shelly earned $15.38 for mowing lawns, $6.25 for cleaning her room, and $12.04 for other chores. How much did she earn last month? 2. BOOKS Micah had $10.52 after he left the bookstore. If he bought a book for $6.39, how much money did he have before he went to the bookstore? 3. FABRIC Noah measured the length of three pieces of cloth. The measurements were 4.29 feet, 3.6 feet, and 2.34 feet. What was the total length of the three pieces of cloth? 4. SNOW Charlotte is happy because it has snowed in her town for three straight days. On Monday, it snowed 3.56 inches. On Tuesday, it snowed more inches. On Wednesday, it snowed 3.07 more inches. What was the total snowfall over the three days? 5. MUSIC During the first week of her vacation, Madison practices playing her flute 5.75 hours. In the following week, she spends 4.2 hours practicing the flute. What is the difference in the amount of time she spends practicing the flute during these weeks? 7. ELEVATION Cheyenne lives on a mountain that is feet above sea level. The mountain her grandmother lives on is feet above sea level. What is the difference in the elevations of these mountains? 6. HIKING Roberto hikes miles on one weekend. The next weekend he hikes 30 miles. How much less is the distance he hiked on the first weekend than the distance he hiked on the second weekend? 8. GARAGE SALE Clinton had his sister sell some of their toys at a garage sale. Clinton makes $12.94 at the sale, and his sister makes $ How much less did Clinton make at the garage sale than his sister? 36 Course 1 Chapter 3 Compute with Multi-Digit Numbers

5 Lesson 1 Reteach Add and Subtract Decimals Example 1 Find the sum of 3.25 and Estimate or The sum is Line up the decimal points. Annex a zero so that both numbers have the same number of decimal places. Add as you would add whole numbers. Place the decimal point. Example 2 Find the difference of and Estimate or Line up the decimal points Subtract as with whole numbers. The difference is Exercises Find each sum or difference Course 1 Chapter 3 Compute with Multi-Digit Numbers 35

6 Lesson 1 Skills Practice Add and Subtract Decimals Find each sum or difference Gasoline prices are given to the nearest thousandth of a dollar. If a gallon of gasoline costs $3.499 and increases $0.09, what is the price of gasoline after the increase? 14. The area of Max s room, not including his closet, is square feet. The area of his closet is square feet. What is the area of his room, including the closet? 36 Course 1 Chapter 3 Compute with Multi-Digit Numbers

7 Multi-Part Lesson 1 PART A NAME DATE PERIOD Enrich Exchange Rates Americans who travel to different countries usually have to exchange some United States dollars for the currency of the country they are in. The exchange rate tells you how much one currency is worth in terms of another. The table below shows some recent exchange rates of several countries. Exchange 1 unit from: USD $ GBP CAD C$ EUR AUD A$ Exchange Rate: USD $ GBP CAD C$ EUR AUD A$ Key: USD ($) = United States dollars, GBP ( ) = British pound sterling, CAD (C$) = Canadian dollars, EUR ( ) European Euros, AUD (A$) = Austrailian dollars The exchange rate from U.S. dollars (USD) to British pound sterling (GBP) is to 1. This means that you need $ to buy 1. Although exchanges rates are calculated to six digits after the decimal point, it is more practical to talk about exchange rates rounded to two decimal places. Exercises 1. Round the exchange rates to two decimal places. USD $ GBP CAD C$ EUR AUD A$ USD $ GBP CAD C$ EUR AUD A$ 2. About how many euros ( ) would you get in exchange for 80? 3. About how many Australian dollars (A$) would you get in exchange for $2,000? Copyright Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc. 4. About how many Canadian dollars (C$) would you get in exchange for 300? 16 Course 1 Multiply and Divide Decimals

8 NAME DATE PERIOD Lesson 2 Extra Practice Estimate Products Estimate each product Sample answers are given = or or or or or or or or or or or or or 600 Course 1 Chapter 3 Compute with Multi-Digit Numbers

9 Lesson 2 Homework Practice Estimate Products Estimate each product SPEED A car moving at 35 miles per hour travels a distance of 51.3 feet each second. About how far does the car travel in 7.1 seconds? 17. DINING OUT The prices for a complete meal at a local restaurant average about $7.75 per person. About how much would a family of six expect to pay for a meal? Use estimation to determine whether each answer is reasonable. If the answer is reasonable, write yes. If not, write no and provide a reasonable estimate = = Course 1 Chapter 3 Compute with Multi-Digit Numbers 37

10 Lesson 2 Problem-Solving Practice Estimate Products Estimate each product. 1. BIKING Mr. Chen can bike about 12.8 miles per hour. About how many miles can he ride in 3.7 hours? 2. BILLS Renee wants to figure out how much it costs her per year for her phone service. Her monthly bill is $ About how much does it cost for one year of service? 3. COOKIES One package of cookie mix contains 7.8 ounces of mix. About how many ounces of mix would there be in 6 packages of cookie mix? 4. MOVIES Mr. Smith takes his children and a few of their friends to the movies and buys each of them a ticket. If admission for the children is $5.75 each for a total of 8 children, about how much should Mr. Smith expect to spend for their tickets? 5. RUNNING Corey is training to be a distance runner. His time for 6 miles is 37 minutes, 10 seconds. If he keeps the same pace for 6 more miles, about how long will it take him for the entire run? 7. FUN The prices in the table show the cost of each activity at the Fun Place. About how much would it cost for 4 people to play miniature golf? Miniature Golf $3.25 Go-Karts $3.75 Skating $ DISTANCE The distance from Charlie s home to school is 1.6 miles. If he walks to school and back, about how far will Charlie have walked? 8. BIRDHOUSES It takes Craig 2.5 hours to build a birdhouse. He wants to build five birdhouses for his yard. About how long will it take him to build all five birdhouses? 38 Course 1 Chapter 3 Compute with Multi-Digit Numbers

11 Lesson 2 Reteach Estimate Products When estimating a product, round to the nearest whole number by looking at the digit in the tenths place and rounding down when the digit is 4 or less and up when the digit is 5 or higher. Example 1 Estimate a Product Estimate Round 5.8 to The product is about 42. Example 2 Estimate a Product Estimate Round 9.6 to Round 4.2 to The product is about 40. Exercises Estimate each product Course 1 Chapter 3 Compute with Multi-Digit Numbers 37

12 Lesson 2 Skills Practice Estimate Products Estimate each product Use estimation to determine whether each answer is reasonable. If the answer is reasonable, write yes. If not, write no and provide a reasonable estimate , = 77, = 4, Course 1 Chapter 3 Compute with Multi-Digit Numbers

13 Multi-Part Lesson 1 PART C NAME DATE PERIOD Enrich Multiply Decimals by Whole Numbers The area of a rectangle can be found by multiplying its length by its width. Area = length width 4.1 cm Area = 3 cm 4.1 cm Area = 12.3 cm 2 The area of the rectangle is 12.3 square centimeters. 3 cm Find the area of each rectangle. Write the area inside the rectangle it measures. 2 in. 2 in. 2.8 in. 6 in. 0.7 in. 1.8 in. 2.8 in. 4.6 in. 8.3 in. 1 in. 4 in. 2 in. 3.7 in. 1.8 in. 0.7 in. 3.7 in. 4 in. 1 in. 6 in. 1 in. Copyright Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc. 22 Course 1 Multiply and Divide Decimals

14 NAME DATE PERIOD Lesson 3 Extra Practice Multiply Decimals by Whole Numbers Multiply Course 1 Chapter 3 Compute with Multi-Digit Numbers

15 Lesson 3 Homework Practice Multiply Decimals by Whole Numbers Multiply ERASERS Vernon buys 12 pencil erasers. Each costs $0.85. How much does Vernon spend on the erasers before tax? 18. SOUP Hot n Spicy Soup costs $2.39 a can. Brand X Soup costs $1.93 a can. Which costs more, 10 cans of Hot n Spicy, or 12 cans of Brand X? What is the difference? 19. SHOPPING Basketballs sell for $27.99 each at the Super D and for $21.59 each at the Bargain Spot. If the coach buys a dozen basketballs, how much can he save by buying them at the Bargain Spot? Justify your answer. 20. SCHOOL Jaimie purchases 15 pencils at the school bookstore. They cost $0.30 each. How much did she spend on pencils? Course 1 Chapter 3 Compute with Multi-Digit Numbers 39

16 Lesson 3 Problem-Solving Practice Multiply Decimals by Whole Numbers 1. COOKING Norberto uses three 14.7-ounce cans of chicken broth when he makes his tortilla soup. How many total ounces of chicken broth does he use? 2. TIME Amanda works on a farm. It takes her 2.25 hours to drive to town and back. She usually goes to town twice a week to get supplies. How much time does Amanda spend driving if she takes 8 trips to town each month? 3. EXERCISE The local health club is advertising a special for new members: no initiation fee to join and only $34.50 per month for the first year. If Andy joins the health club for one year, how much will he spend on membership? 4. BIKING In order to train for a crossstate biking trip, Julie rides her bike miles five times a week. How many total miles does she ride each week? 5. MONEY David is building a doghouse and needs bolts and washers from the hardware store. How much will David pay for 16 bolts that are 4 inches long and a washer for each? 3-inch bolts 4-inch bolts washers $0.87 each $0.92 each $0.12 each 7. COSTUMES K.J. is making costumes for this year s parade. The pattern she is using calls for yards of fabric for each costume. How many yards of fabric will she need to make 34 costumes? 6. INSECTS One wing of a Royal Moth is 0.75 inch across. How wide is the moth s wingspan when both wings are open? 8. POOL PASSES The Girl Scouts are going to the pool. It will cost them $2.50 per person to go and there are 10 people going. What will the total cost be? 40 Course 1 Chapter 3 Compute with Multi-Digit Numbers

17 Lesson 3 Reteach Multiply Decimals by Whole Numbers When you multiply a decimal by a whole number, you multiply the numbers as if you were multiplying all whole numbers. Then you use estimation or you count the number of decimal places to decide where to place the decimal point. If there are not enough decimal places in the product, annex zeros to the left. Example 1 Find using models. Model 5 groups of 0.36 on a decimal model. Rearrange the columns and small squares to fill as many whole grids as possible. So, = 1.8. Example 2 Find Method 1 Use estimation. Round 6.25 to or Since the estimate is 30, 5 place the decimal point after 31. Example 3 Find There are four decimal places Exercises Multiply. Annex a zero on the left of 141 to make four decimal places. Method 2 Count decimal places. There are two places to the right of the decimal point. Count the same number of decimal places from right to left Course 1 Chapter 3 Compute with Multi-Digit Numbers 39

18 Lesson 3 Skills Practice Multiply Decimals by Whole Numbers Multiply Course 1 Chapter 3 Compute with Multi-Digit Numbers

19 Multi-Part Lesson 1 PART E NAME DATE PERIOD Enrich A Logic Puzzle Here is a puzzle that will help you brush up on your logical thinking skills. The product is in both the circle and the triangle, but not in the square. Place the product in the diagram at the right Write in the correct region of the diagram Use the given information to place the product in the diagram above. 1. The product is in both the triangle and the square, but not in the circle. 2. The product is in the triangle, but not in the circle or the square. 3. The product is not in the circle, the square, or the triangle. 4. The product is in both the square and the circle, but not in the triangle. 5. The product is in the circle, but not the triangle or the square. 6. The product is in the circle, the square, and the triangle. 7. The product is in the square, but not the circle or triangle. 8. If you did all the calculations correctly, the sum of all the numbers in the diagram should be a nice number. What is the sum? Copyright Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc. 28 Course 1 Multiply and Divide Decimals

20 NAME DATE PERIOD Lesson 4 Extra Practice Multiply Decimals by Decimals Multiply Course 1 Chapter 3 Compute with Multi-Digit Numbers

21 Lesson 4 Homework Practice Multiply Decimals by Decimals Multiply MINING A mine produces 42.5 tons of coal per hour. How much coal will the mine produce in 9.5 hours? 12. SHOPPING Ms. Morgan bought 3.5 pounds of bananas at $0.51 a pound and 4.5 pounds of pineapple at $1.19 a pound. How much did she pay for the bananas and pineapple? Course 1 Chapter 3 Compute with Multi-Digit Numbers 41

22 Lesson 4 Problem-Solving Practice Multiply Decimals by Decimals 1. GIFTS Colin is making soap for gifts. The table shows the cost of the scented oils needed to make each kind of soap. He needs 1.5 ounces of scented oil to make a batch of soap. If he wants to make 2 batches of lavender soap and 2 batches of vanilla soap, how much money will he need for the oils? 2. GROCERY Iona s favorite peaches are $2.50 per pound at the local farmers market. She bought 3.5 pounds of the peaches. How much did she spend? Oil almond lavender vanilla melon Cost $1.23 per ounce $1.54 per ounce $1.65 per ounce $1.12 per ounce 3. SHOPPING Jennifer is buying new school clothes. The items she wants to buy add up to $ before sales tax. Sales tax is calculated by multiplying the total amount by What is the amount of sales tax for the items? 5. INCOME Ishi makes $8.50 an hour rolling sushi at a restaurant. His paycheck shows that he worked hours over the past two weeks. How much did Ishi make before taxes? 4. DRIVING Ana bought a van that holds gallons of gas and gets an average of 15.5 miles per gallon. How many miles can she expect to go on a full tank? 6. TRAVEL Manny is on vacation in France. He has rented a car to drive kilometers from Paris to Brussels and wants to figure out the distance in miles. Since 1 kilometer is equal to about 0.62 mile, he needs to multiply the total kilometers by About how many miles will Manny drive? 42 Course 1 Chapter 3 Compute with Multi-Digit Numbers

23 Lesson 4 Reteach Multiply Decimals by Decimals When you multiply a decimal by a decimal, multiply the numbers as if you were multiplying all whole numbers. To decide where to place the decimal point, fi nd the sum of the number of decimal places in each factor. The product has the same number of decimal places. Example 1 Find Estimate: 5 6 or one decimal place 6.13 two decimal places three decimal places The product is Compared to the estimate, the product is reasonable. Example 2 Find Estimate: or one decimal place 0.02 two decimal places Annex a zero to make three decimal places. The product is Compared to the estimate, the product is reasonable. Exercises Multiply Course 1 Chapter 3 Compute with Multi-Digit Numbers 41

24 Lesson 4 Skills Practice Multiply Decimals by Decimals Multiply Course 1 Chapter 3 Compute with Multi-Digit Numbers

25 Multi-Part Lesson 3 PART C NAME DATE PERIOD Enrich Decibels The human ear can detect an extremely wide range of sound levels. To measure the power of sound waves detectable by the human ear, decibels (db) are used. The lowest measurement detectable is called the Threshold of Hearing, or TOH. The TOH is given a measurement of 0 decibels. A sound that is times louder is given a measurement of 20 decibels. A sound that is times louder than the TOH is given a measurement of 30 decibels. 1. For each of the sounds listed in the table, determine how many times louder than the threshold of hearing it is. Sound Decibels Times as Loud as TOH Rustling leaves 10 db Whisper 20 db Refrigerator humming 40 db Normal conversation 60 db Busy street traffic 70 db Vacuum cleaner 80 db Subway 90 db Copyright Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc. 2. Explain how you determined the number of times as loud as the TOH each sound is. 3. How many times as loud as a whisper is a normal conversation? 4. How many times as loud as rustling leaves is a whisper? 5. How many times as loud as rustling leaves is a subway? 6. How many times as loud as a refrigerator humming is a vacuum cleaner? 7. How many times as loud as a normal conversation is busy street traffic? Explain how you found your answer. Course 1 Multiply and Divide Decimals 63

26 NAME DATE PERIOD Lesson 5 Extra Practice Divide Multi-Digit Numbers Find each quotient R R R R R R R R R R R R R R7 Course 1 Chapter 3 Compute with Multi-Digit Numbers

27 Lesson 5 Homework Practice Divide Multi-Digit Numbers Find each quotient. 1. 1, , , , , , , , , READING Keri is reading a novel that has 650 pages. She has 25 days to finish the book. If Keri reads the same number of pages each day, how many pages does she read each day? 17. SEATING The new baseball stadium holds 64,506 people. There are 26 gates where people enter the ballpark. The same number of people entered each gate. How many people entered the first gate? Course 1 Chapter 3 Compute with Multi-Digit Numbers 45

28 Lesson 5 Problem-Solving Practice Divide Multi-Digit Numbers 1. HOMEWORK Lisa solved 448 math problems for homework over 28 days. If she solved the same number of problems each day, how many problems did she solve per day? 2. CHARITY Luis was in charge of collecting money for a group of charities. He collected $979 for 11 charities. If the money was divided evenly, how much was given to each charity? 3. MEALS Sandra helped serve meals to 25 families. Each family received the same amount of food. If she served 275 pounds of food, how many pounds of food did each family receive? 4. SALARY Joshua works for a computer company and receives an annual salary of $38,480. He receives 26 equal pay checks during the year. How much does he receive in each pay check? 5. FOOTBALL The football team is raising money to have a new turf field installed. The cost of the turf field is $48,780. The team has 18 months to raise the money. How much do they need to raise each month? 7. TRAVEL Mr. Santiago has a flight from New York to Paris that covers a distance of 3,636 miles. If the plane travels at 520 miles per hour, about how long will it take to get to Paris? 6. WINDOWS A window washing company has a contract to wash 3,082 windows on a 23-story building. If there are the same number of windows on each floor, how many windows are there on each floor? 8. DELIVERIES Mr. Thomas is delivering bricks to a construction site. His truck holds 387 bricks at one time. The builder has ordered 2,800 bricks. How many trips will Mr. Thomas have to make to deliver all the bricks? 46 Course 1 Chapter 3 Compute with Multi-Digit Numbers

29 Lesson 5 Reteach Divide Multi-Digit Numbers When one number is divided by another, the result is called a quotient. The dividend is the number that is divided and the divisor is the number used to divide another number. Example Find Estimate or R The quotient is 19 R22. Exercises Find each quotient. Divide each place-value position from left to right. Since = 22 and 22 < 30, 22 is the remainder , , , Course 1 Chapter 3 Compute with Multi-Digit Numbers 45

30 Lesson 5 Skills Practice Divide Multi-Digit Numbers Find each quotient , , , Course 1 Chapter 3 Compute with Multi-Digit Numbers

31 Multi-Part Lesson 2 PART A NAME DATE PERIOD Enrich Quilts A local shop sells quilts. Several of its quilts and quilt patterns are shown below. The length and width of each quilt are given along with its price. Estimate the area of each quilt. Then estimate its price per square foot feet by 5 feet, $ feet by 6.75 feet, $ feet by 6 feet, $ feet by 8.25 feet, $ Copyright Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc. 5. How accurate do you think your four estimates are of the price per square foot? Explain your answer. 34 Course 1 Multiply and Divide Decimals

32 NAME DATE PERIOD Lesson 6 Extra Practice Estimate Quotients Estimate each quotient Sample answers are given or or or or or or or or or or or or or or 8 Course 1 Chapter 3 Compute with Multi-Digit Numbers

33 Lesson 6 Homework Practice Estimate Quotients Estimate each quotient MONEY Mr. Briggs paid $ for a set of four tires for his truck. About how much was the cost per tire? 17. CHECKERS Annika bought 9 checker sets for her checkers club. She paid $87.84 before tax. About how much did each checker set cost? Use estimation to determine whether each answer is reasonable. If the answer is reasonable, write yes. If not, write no and provide a reasonable estimate = = 5.4 Course 1 Chapter 3 Compute with Multi-Digit Numbers 47

34 Lesson 6 Problem-Solving Practice Estimate Quotients Estimate each quotient. 1. SKATING Ms. Johnson skates 19.7 miles in 2.8 hours. Estimate her speed in miles per hour. 2. TELEVISION Jacob s bill for cable TV was $65.33 last month. About how much did he pay per day for television service? 3. COOKIES Charissa is baking cookies for a bake sale. She sells a box of cookies for $4.80. If each box contains nine cookies, for about how much does she sell each cookie. 4. DOG FOOD The local kennel needs to buy dog food. Which dog food will save the kennel the most money? Dogs Luv It 150 pounds for $53.50 Kibble Chow 75 pounds for $ RUNNING Corey ran a total of 22.8 miles over a period of six days. If he ran the same number of miles each day, about how many did he run each day? 7. LAUNDRY Jim s bottle of laundry detergent is large enough to do 26 loads of wash, and the bottle contains 3.12 quarts of liquid. About how much detergent does it take to wash one load of laundry? 6. SPORTS Carley is the team manager for the football team and is responsible for supplying them with drinks at the games. At each game, the team drinks 14.2 gallons of sports drink. If Carley has 88.3 gallons of sports drink, will she have enough to get them through their 8-game season? Why or why not? 8. CARPET Pete bought square feet of carpeting for $1,316. About how much does the carpet cost per square foot? 48 Course 1 Chapter 3 Compute with Multi-Digit Numbers

35 Lesson 6 Reteach Estimate Quotients When estimating a quotient, fi nd numbers that are compatible with each other to make it easier to divide mentally. Example 1 Estimate a Quotient Estimate The quotient is about 3. 3 Exercises Estimate each quotient. 15 Round 5.7 to 5 since 15 and 5 are compatible numbers Course 1 Chapter 3 Compute with Multi-Digit Numbers 47

36 Lesson 6 Skills Practice Estimate Quotients Estimate each quotient Use estimation to determine whether each answer is reasonable. If the answer is reasonable, write yes. If not, write no and provide a reasonable estimate = = = = 6 48 Course 1 Chapter 3 Compute with Multi-Digit Numbers

37 Multi-Part Lesson 2 PART C NAME DATE PERIOD Enrich Unit Pricing The unit price of an item is the cost of the item given in terms of one unit of the item. The unit might be something that you count, like jars or cans, or it might be a unit of measure, like ounces or pounds. You can find a unit price using this formula. TUNA 89 6-ounce can unit price = cost of item number of units For example, you find the unit price of the tuna in the ad at the -609 right by finding the quotient The work is shown below 299 the ad. Rounding the quotient to the nearest cent, the unit price -249 is $0.15 per ounce Find a unit price for each item pound bag CARROTS $ ounce jar PEANUT BUTTER $ Grade A Jumbo EGGS Dozen $1.59 Give two different unit prices for each item. 4. Frozen BURRITOS 5-ounce pkg 2 for $1.39 Circle the better buy. 7. Mozzarella Cheese 3/$4 10-ounce pkg 5. Mozzarella Cheese 2/$3 18-ounce pkg Purr-fect CAT FOOD 3/$1 3-ounce can Dee-Light Chicken Wings $ pound bag Old Tyme SPAGHETTI SAUCE 12-ounce jars 2/$3 Top Q Chicken Wings $ ounce bag Copyright Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc. 40 Course 1 Multiply and Divide Decimals

38 NAME DATE PERIOD Lesson 7 Extra Practice Divide Decimals by Whole Numbers Divide. Round to the nearest tenth if necessary Course 1 Chapter 3 Compute with Multi-Digit Numbers

39 Lesson 7 Homework Practice Divide Decimals by Whole Numbers Divide. Round to the nearest tenth if necessary WEATHER What is the average monthly precipitation in Arches National Park? Round to the nearest hundredth if necessary. Precipitation in Arches National Park Month Jan Feb Mar Apr May Jun Jul Aug Sept Oct Nov Dec Precipitation (in.) SHOPPING A 3-pack of boxes of juice costs $1.09. A 12-pack of boxes costs $4.39. A case of 24 boxes costs $8.79. Which is the best buy? Explain your reasoning. Course 1 Chapter 3 Compute with Multi-Digit Numbers 49

40 Lesson 7 Problem-Solving Practice Divide Decimals by Whole Numbers 1. ENTERTAINMENT Frank, Gina, Judy, and Connie are splitting their dinner bill. After tip, the total is $ How much does each owe if they split the bill four ways? 2. FOOD There are 25 servings in a 12.5-ounce bottle of olive oil. How many ounces are in a serving? 3. RUNNING Isabella has found that she stays the fittest by running various distances and terrains throughout the week. On Mondays she runs 2.5 miles, on Tuesdays 4.6 miles, on Thursdays 6.75 miles, and on Saturdays 4.8 miles. What is the average distance Isabella runs on each of the days that she runs? Round to the nearest hundredth of a mile. (Hint: To find the average, add the values and divide by the number of values.) 5. CONSTRUCTION It took Steve and his construction crew 8 months to build a house. After expenses, he was left with $24, for himself. On average, how much did Steve make per month? Round to the nearest dollar. 4. BUSINESS Katherine spends $1, each month for rent and supplies to run her hair salon. If she charges $18 for a haircut, how many haircuts must Katherine do to cover her monthly expenses? Round to the nearest whole number. 6. GRADES Shane wants to figure out what grade he is getting in math. His test scores were 85.6, 78.5, 92.5, 67, and What was his average test score? What grade will he receive? Grade Average Score A B C D F Course 1 Chapter 3 Compute with Multi-Digit Numbers

41 Lesson 7 Reteach Divide Decimals by Whole Numbers When you divide a decimal by a whole number, place the decimal point in the quotient above the decimal point in the dividend. Then divide as you do with whole numbers. Example 1 Find Estimate: 9 9 = Place the decimal point directly above the decimal point in the dividend Divide as with whole numbers = 0.97 Compared with the estimate, the quotient is reasonable. Example 2 Find Estimate: = Place the decimal point Annex a zero to continue dividing = Compared with the estimate, the quotient is reasonable. Exercises Divide Course 1 Chapter 3 Compute with Multi-Digit Numbers 49

42 Lesson 7 Skills Practice Divide Decimals by Whole Numbers Divide. Round to the nearest tenth if necessary Course 1 Chapter 3 Compute with Multi-Digit Numbers

43 Course 1 Chapter 3 Compute with and Multi-Digit Numbers 23 Enrich It s in the Cards Below each set of cards, a quotient is given. Use the digits on the cards to form a division sentence with that quotient. Use as many zeros as you need to get the correct number of decimal places. For example, this is how to find a division sentence for the cards at the right You know that 24 3 = 8. So, one division sentence is = Sample answers given. Quotient: Quotient: Quotient: 0.04 Quotient: Quotient: Quotient: Quotient: Quotient: Quotient: Quotient: Quotient: Quotient: Quotient: CHALLENGE Use the cards at the right. Write four different division sentence that have the quotient ; ; ;

44 NAME DATE PERIOD Lesson 8 Extra Practice Divide Decimals by Decimals Divide Course 1 Chapter 3 Compute with Multi-Digit Numbers

45 Lesson 8 Homework Practice Divide Decimals by Decimals Divide WHALES After its first day of life, a baby blue whale started growing. It grew inches. If the average baby blue whale grows at a rate of 1.5 inches a day, for how many days did the baby whale grow, to the nearest tenth of a day? 11. LIZARDS The two largest lizards in the United States are the Gila Monster and the Chuckwalla. The average Gila Monster is meter long. The average Chuckwalla is meter long. How many times as long is the Gila Monster as the Chuckwalla, to the nearest hundredth? Course 1 Chapter 3 Compute with Multi-Digit Numbers 51

46 Lesson 8 Problem-Solving Practice Divide Decimals by Decimals MARATHON For Exercises 1 and 2, use the table that shows course records for the Boston Marathon. Course Records for the Boston Marathon Division Record Holder Year Time (h) Men s Open Robert Cheruiyot Women s Open Margaret Okayo Men s Wheelchair Ernst Van Dyk Women s Wheelchair Jean Driscoll The Boston Marathon is 26.2 miles. Use the times shown in the table to calculate the miles per hour for each division winner. Round to the nearest thousandth. 2. To the nearest hundredth, how many times as great was the men s open time as the women s wheelchair time? 3. DRIVING The Martinez family drove 48.7 miles to the river. It took them 1.2 hours to get there. How fast did they drive? Round to the nearest whole number. 5. SCALE MODEL Matt is making a scale model of a building. The model is 3.4 feet tall. The actual building is feet tall. How many times as great is the actual building as the model? 4. SHOPPING Nikki is buying some refrigerator magnets for her friends. Her total bill is $ If magnets are $0.80 each, how many magnets is she buying? 6. COOKING Yori has cups of cupcake batter. If each cupcake uses 0.75 cup of batter, how many cupcakes can Yori make? 52 Course 1 Chapter 3 Compute with Multi-Digit Numbers

47 Lesson 8 Reteach Divide Decimals by Decimals When you divide a decimal by a decimal, multiply both the divisor and the dividend by the same power of ten. Then divide as with whole numbers. Example 1 Find Estimate: 10 5 = 2 Multiply by 10 to make a whole number Place the decimal point Divide as with whole numbers Multiply by the same number, Annex a zero to continue divided by 5.2 is Compare the quotient with the estimate. Check = Example 2 Find Place the decimal point Divide. - 4 Multiply each by Write a zero in the dividend - 10 and continue to divide divided by 0.02 is Check = 4.09 Exercises Divide Course 1 Chapter 3 Compute with Multi-Digit Numbers 51

48 Lesson 8 Skills Practice Divide Decimals by Decimals Divide Course 1 Chapter 3 Compute with Multi-Digit Numbers

49 Homework Practice Problem-Solving Investigation: Look for a Pattern Mixed Problem Solving Use the look for a pattern strategy to solve Exercises SNOW Javan built a 4.6-foot tower of snow in his yard. Later in the day, the weather became warmer. After one hour, the tower was 4.4 feet tall, and after two hours, it was 4.2 feet tall. If the pattern continues, how tall will the tower be after 10 hours? 5. EXERCISE At the community center, 9 boys and 9 girls are playing singles table tennis. If each girl plays against each boy exactly once, how many games are played? 2. DECORATIONS Bonita cut out stars for a school program. She first cut out a 4-centimeter star. The she cut out a 3.5-centimeter star, followed by a 3-centimeter star. If she follows this pattern, what size will the next star be? 6. RECIPE A recipe for potato salad calls for one teaspoon of vinegar for every 2 teaspoons of mayonnaise. How many teaspoons of vinegar are needed for 16 teaspoons of mayonnaise? 3. NUMBER SENSE Describe the pattern below. Then find the next three numbers. 21, 24.5, 28, 31.5, 35, Use any strategy to solve Exercises MONEY Marci found $1.42 in her coat pocket. She had $4.85 in her backpack. Is $5.50, $6.50, or $7.50 a more reasonable estimate for how much money she had altogether? 7. SEATING Tobias is having friends over for dinner. The dinner table is 6 feet by 3 feet. If each friend will need about 2 feet of table space to sit comfortably, what is the maximum number of friends Tobias can invite to dinner? 8. SWIMMING Heidi can swim one lap in the pool in 36 seconds. How long will it take her to swim 3 laps? Course 1 Chapter 3 Compute with Multi-Digit Numbers 43

50 Problem-Solving Practice Problem-Solving Investigation: Look for a Pattern 1. SEATING A rectangular table seats four people on one side and 2 people on each end. How many seats are available if the ends of 5 tables are placed together? 2. SAVINGS Melinda started a savings account and plans to save $2 the first week, $4 the second week, and $8 the third week. If her pattern of saving continues, how much will she be saving in the fifth week? 3. TRACK A track and field coach plans the number of meters her team will sprint in each practice. The number of meters for the first four practices are 50 meters, 65 meters, 80 meters, and 95 meters. How many meters will be for the fifth practice? 5. MARCHING BAND A marching band formation has 12 rows. Three band members are in the first row, 6 band members in the second row, 9 band members in the third row, and so on. How many band members are in the 12 th row? 4. CONCERT The last row of a balcony has 65 seats. The row in front of it has 62 seats, then the next row has 59 seats. If the balcony has 8 rows, how many seats are in the first row of the balcony? 6. BREAD The table shows the cost of loaves of bread. How much will 7 loaves of bread cost? Cost of Loaves of Bread Loaves Cost ($) Course 1 Chapter 3 Compute with Multi-Digit Numbers

51 Reteach Problem-Solving Investigation: Look for a Pattern You can use the look for a pattern problem-solving strategy to solve a problem. Example QUILTING Paige uses different size squares to make a quilt. The smallest square is 2.5 inches on a side. The next three squares have sides of 3.75, 5, and 6.25 inches. If the pattern continues, what are the lengths of the sides of the next two squares? Understand Plan Solve You know the lengths of the 4 squares. You need to find the lengths of the next two squares. Look for a pattern to find the lengths of the sides of the next two squares. Use a table to find a pattern. Square Side Length Check The length of the sides of the squares increases 1.25 with each side. So, the next two lengths of sides will be 7.5 and Sketch the squares and measure with a ruler. Exercise DISPLAYS There are 64 cans used in the first row of a display. The second row uses 49 cans, and the third row uses 36 cans. If the pattern continues, how many cans are used in the fifth row of the display? What is the pattern? Course 1 Chapter 3 Compute with Multi-Digit Numbers 43

52 Skills Practice Problem-Solving Investigation: Look for a Pattern Solve. 1. ART A sculptor is using a pattern of glass cubes to create a sculpture with 5 sections. The first section has 4 cubes, the second section has 8 cubes, and the third section has 16 cubes. If the pattern continues, how many cubes will be in the fifth section? 2. SCRAPBOOKING Mika is making a pattern of circles. The smallest circle has a diameter of 8.2 centimeters. The next circle has a diameter of 12.4 centimeters, and the circle after that has a diameter of 16.6 centimeters. What is the diameter of the sixth circle? 3. PYRAMID The bottom layer of a pyramid has 150 blocks. The layer above the bottom has 120 blocks. The third layer from the bottom has 90 blocks. If the pattern continues, how many blocks will be in the next two layers? 4. APPLES At a farmer s market, 3 apples cost $1.50, 6 apples cost $3, and 9 apples cost $4.50. How much will 12 apples cost? 44 Course 1 Chapter 3 Compute with Multi-Digit Numbers