1ACE Exercise 20. Name Date Class

Transcription

1 1ACE Exercise 20 Investigation Gregory walks 1.8 miles from his home to school. Halfway between his home and school there is a music store. This morning, he wants to stop at the store before school. a. If he is 0.36 miles away from home, how much more does he need to walk, in miles, to get to the store? HINT How many miles from Gregory s house is the music store? b. If he is 0.36 miles away from home, how many miles does he have left to walk to school? HINT How many miles total does Gregory walk from his home to school? 42

2 2ACE Exercise 33 Investigation Ten-year-old Chi learned a lot of math from his older brother, Shing. One day, Shing tells him that as a shortcut to finding the answer, when you multiply a number by 10, you just add a zero. a. With Shing s idea in his mind, Chi says, To find 10 20, I just add a zero. So, = 20. How would you correct him? HINT What should be the answer to 10 20? HINT How would you change the shortcut Shing told Chi to make it clearer? b. After Chi realizes that adding zero actually means putting an extra zero at the end, he says, equals by putting the extra zero at the end. Is he right this time? How would you rephrase putting an extra zero at the end in case the other number is a decimal number? HINT What would the shortcut be if you are multiplying 10 by a decimal? Explain why your suggestion works. c. How can you find the result of multiplying by 100; 1,000; or 10,000 using a similar strategy? HINT What would the shortcut be if you multiply a number by: 100? 1,000? 10,000? 43

3 3ACE Exercise 1 4 Investigation 3 For Exercises 1 4, decide what operation is needed (,,, ) to answer the question. 1. Akiko s dog has 3 puppies. They weigh 2.6 pounds, 2.74 pounds, and 3.1 pounds. How much more does the heaviest puppy weigh than the lightest puppy? What operation (+,,, ) can you use to answer this question? Explain. 2. Angie is making wreaths to sell at a craft show. She has 6.5 yards of ribbon. 1 Each wreath has a bow made from 13 yards of ribbon. How many bows can she make? What operation (+,,, ) can you use to answer this question? Explain. 3. Mrs. Doran has three grandchildren. She takes them to lunch where kids meals are $2.95 each. How much will the three kids meals cost? What operation (+,,, ) can you use to answer this question? Explain. 4. Loren is putting brick along both edges of the 21-meter walkway up to his house. Each brick is 0.26 meters long. Loren is placing the bricks end to end. How many bricks does he need? What operation (+,,, ) can you use to answer this question? Explain. 44

4 4ACE Exercise 6 Investigation 4 6. Jen and Sarah go to lunch at the Green Grill. Their meal totals $ a. The sales tax is 6%. What is the total cost with the tax? b. They want to leave a 20% tip based in the total cost before the tax. How much tip should they leave? c. Describe two strategies that Jen and Sarah can use to figure the amount of the tip

5 5ACE Exercise 13 Investigation You and your friends are going out to eat. You decide to pool your money and order several dishes and appetizers to share. You have $75 altogether. If the tax is 5% and you want to leave a 15% tip (on the price of food before tax), what is the maximum you can spend? HINT Think of the maximum amount of money you can spend on food as a percent (100%). Think of $75 as a percent of what you have altogether, which includes the maximum amount of money you can spend on food (100%) plus the 5% tax plus the 15% tip. If you were to add these amounts together (food + tax + tip), $75 would be what percent? How could you write this problem as a ratio? What is the maximum you can spend on food if you have $75 total? 46

6 5ACE Exercise 13 (Alternative) Investigation You and your friends are going out to eat. You decide to pool your money and order several dishes and appetizers to share. You have $75 altogether. If the tax is 5% and you want to leave a 15% tip (on the price of food before tax), what is the maximum you can spend? HINT Draw a diagram that represents this problem. One is started for you. $75 100% Cost of food 5% tax 15% tip 20% If $75 is 120%, how much is 100% (the amount they can spend on the meal)? How much is 10%? HINT Divide the bar above into equal pieces so that each piece represents 10%. 47

7 Unit Test 1. Solve the following computations. Show your work. a b c d Paul took a trip in May. The price of gasoline that he paid during his trip was $1.50 per gallon. He filled his van 4 times over the trip. The amounts he bought were: gallons gallons gallons gallons a. How much total gasoline did he buy on the trip? 48

8 Unit Test (continued) b. What was his total cost for gasoline on the trip? What is the price of gasoline per 1 gallon Paul paid? What is the total cost of gasoline for all the gas Paul bought? c. His odometer (measures distance traveled) read 23,451.1 miles when he pulled out of his driveway and 24,809.4 miles when he returned. b. How many miles did he travel on the trip? 49