# 1.13

## 1.13

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##### Presentation Transcript

1. 1.13 “I can estimate the results of computations involving whole numbers and decimals, using a variety of strategies.”

2. Why is this important? • How many people like to do things quickly? • Plan for a party. • How many people estimate when you shop to make sure you have enough money? • Estimating saves time. • When are good times to estimate?

3. Vocabulary • Estimate - An estimate is close to the ________ answer. Estimating saves you ________ by making problems ________. • Strategies of Estimating: 1. Make it easier to work with. 2. Front End Estimation 3. Rounding 4. Compatible Numbers

4. What word is a clear indication that you are estimating? ABOUT Estimate the following: 12 \$342 1,953 12,994 \$59.29 939

5. Question? • On Monday, Camille drove 74.9 miles from Union to Columbus. On Tuesday, she drove 142.82 miles from Columbus to Canton. About how many miles did Camille drive in all? • A. 225 miles B. 100 miles • C. 175 miles D. 150 miles

6. Practice • Jon weighed 98 pounds. He gained 21 pounds during the last year. Estimate how many pounds he weighed a year ago. A. About 80 pounds B. About 98 pounds C. About 120 pounds D. About 77 pounds

7. Practice • Willis has to distribute \$2,008 of charity money raised by his classmates among 10 different charities. If he donates the same amount of money to each charity, which is a reasonable estimate of how much money each charity will receive? • A. \$20 • B. \$100 • C. \$200 • D. \$300

8. 1.4 “I can round decimals to a given place value.”

9. Vocabulary • Rounding - one way to find an approximate _________. Use place value to help you round. • Rounding is a strategy of __________.

10. Rule 1 • Underline the place value you are rounding to. Round to the nearest tenths place. 459.46

11. Rule 2 • Draw an arrow to the number to the _________. • If that digit is 4 or less, (Round Down) Keep the number the same. • If the digit is 5 or more, Round up. Round to the nearest tenths place. 459.46

12. Rule 3 • All the numbers to the left of the rounding number stay the ______. • All the numbers to the right of the rounding number become ________. Round to the nearest tenths place. 459.46 459.50

13. Practice • Round the following decimal to the nearest hundredths. • 321.876 • A. 321.800 B. 321.880 C. 321.870 • What is 6.74 rounded to the nearest tenths? • A. 6.70 B. 6.80 C. 6.75

14. Practice • Round 89.155 to the nearest whole number. • A. 90 B. 89.155 C. 89.000 • Round \$34.81 to the nearest dollar. • A. \$34 B. \$35 C. \$35.81

15. What did we learn today? • List: