Today’s Plan: -Conversions to memorize -Order Decimals -Estimate with decimals

1. 11/15/10 Estimate with Decimals Entry Task Learning Target: -I can convert, compare, and order fractions and decimals. I can estimate with decimals. Today’s Plan: -Conversions to memorize -Order Decimals -Estimate with decimals

2. 11/15/10 Estimate with Decimals Conversions to Memorize Number your paper from 1-14 for a practice test. Learning Target: -I can convert, compare, and order fractions and decimals. I can estimate with decimals. Today’s Plan: -Conversions to memorize -Order Decimals -Estimate with decimals

3. 11/15/10 Estimate with Decimals Change each decimal to a fraction in lowest terms, and each fraction to a decimal. • 6. 0.8 = • 7. 0.75 = • 8. 0.5 = • 9. • 10. • 0.3 = • 0.25 = • 0.7 = • 0.9 = • 0.3 = 1 10 11. = 1 4 12. = 2 5 13. = 2 3 = 1 2 3 5 14. = = Learning Target: -I can convert, compare, and order fractions and decimals. I can estimate with decimals. Today’s Plan: -Conversions to memorize -Order Decimals -Estimate with decimals

4. 11/15/10 Estimate with Decimals Write your name on the upper left hand corner of the blank side. Then fold your paper into fourths. Learning Target: -I can convert, compare, and order fractions and decimals. I can estimate with decimals. Today’s Plan: -Conversions to memorize -Order Decimals -Estimate with decimals

5. 11/15/10 Estimate with Decimals Human Number Line: Order Decimals Learning Target: -I can convert, compare, and order fractions and decimals. I can estimate with decimals. Today’s Plan: -Conversions to memorize -Order Decimals -Estimate with decimals

6. 4-1 Estimate with decimals Course 2 Learn to estimate decimal sums, differences, products, and quotients.

7. 4-1 Estimate with Decimals Course 2 Jessie earned $27.00 for baby-sitting. She wants to use the money to buy a ticket to a water park for $14.75 and a souvenir T-shirt for $13.20. To find out if Jessie has enough money to buy both items, you can use estimation. To estimate the total cost of the ticket and the T-shirt, round each price to the nearest dollar, or integer. Then add the rounded values.

8. 4-1 Estimate with Decimals Course 2 Insert Lesson Title Here $14.75 7 7 > 5, so round to $15 $15 $13 $13.20 2 2 < 5, so round to $13 + $28 The estimated cost is $28, so Jessie does not have enough money to buy both items. To estimate decimal sums and differences, round each decimal to the nearest integer and then add or subtract.

9. 4-1 Estimate with Decimals Remember! To round to the nearest integer, look at the digit in the tenths place. If it is greater than or equal to 5, round to the next integer. If it is less than 5, keep the same integer. Course 2 Insert Lesson Title Here

10. 4-1 Estimate with Decimals 4.5 +8.9 +9 Course 2 Insert Lesson Title Here Additional Example 1A: Estimating Sums and Differences of Decimals Estimate by rounding to the nearest integer. A. 4.5 + 8.9 5 5 ≥ 5, so round to 5. 9 > 5, so round to 9. Estimate 14

11. 4-1 Estimate with Decimals 28.3 –11.7 –12 Course 2 Insert Lesson Title Here Additional Example 1B: Estimating Sums and Differences of Decimals Estimate by rounding to the nearest integer. B. 28.3 – 11.7 28 3 < 5, so round to 28. 7 > 5, so round to 12. Estimate 16

12. 4-1 Estimate with Decimals 57.2 + (–24) + (–23.72) Course 2 Insert Lesson Title Here Additional Example 1C: Estimating Sums and Differences of Decimals Estimate by rounding to the nearest integer. C. 57.2 + (–23.72) 57 2 < 5, so round to 57. 7 > 5, so round to –24. 33 Estimate

13. 4-1 Estimate with Decimals 6.8 +4.9 +5 Course 2 Insert Lesson Title Here Try This: Example 1A Estimate by rounding to the nearest integer. A. 6.7 + 4.9 7 8 ≥ 5, so round to 7. 9 > 5, so round to 5. Estimate 12

14. 4-1 Estimate with Decimals 19.2 –13.6 –14 Course 2 Insert Lesson Title Here Try This: Example 1B Estimate by rounding to the nearest integer. B. 19.2 – 13.6 19 2 < 5, so round to 19. 6 > 5, so round to –14. Estimate 5

15. 4-1 Estimate with Decimals 61.3 + (–19) + (–18.84) Course 2 Insert Lesson Title Here Try This: Example 1C Estimate by rounding to the nearest integer. C. 61.3 + (–18.84) 61 3 < 5, so round to 61. 8 > 5, so round to –19. 42 Estimate

16. 4-1 Estimate with Decimals Course 2 You can use compatible numbers when estimating. Compatiblenumbers are numbers that replace the numbers in the problem and are easier to use.

17. 4-1 Insert Lesson Title Here Course 2

18. 4-1 Estimate with Decimals 45.99  2.31  2 Course 2 Insert Lesson Title Here Additional Example 2A: Estimating with Decimals Use compatible numbers to estimate. A. 45.99 · 2.31 Round to the nearest multiple of 10. 50 3 < 5, so round to 2. 100 Estimate

19. 4-1 Estimate with Decimals Course 2 Insert Lesson Title Here Additional Example 2B: Estimating with Decimals Use compatible numbers to estimate. B. 51.33 ÷ (–7.98) 51 is prime, so round to 49. 51.33 49 –7.98 –7 divides into 49 without a remainder. –7 49 ÷ –7 = –7 Estimate

20. 4-1 Estimate with Decimals 39.62  4.99  5 Course 2 Insert Lesson Title Here Try This: Example 2A Use compatible numbers to estimate. A. 39.62 · 4.99 Round to the nearest multiple of 10. 40 9 > 5, so round to 5. 200 Estimate

21. 4-1 Estimate with Decimals Course 2 Insert Lesson Title Here Try This: Example 2B Use compatible numbers to estimate. B. 19.42 ÷ (–4.88) 19 is prime, so round to 20. 19.42 20 –4.88 –5 divides into 20 without a remainder. –5 20 ÷ –5 = –4 Estimate

22. 4-1 Estimate with Decimals Course 2 Insert Lesson Title Here Additional Example 3: Application Cara spent $58.80 on 4.8 pounds of lobster and calculated that she spent about $12 per pound of lobster. Use estimation to check whether her calculation is reasonable. $60 $58.80 Round to the nearest multiple of 10. 8 > 5, so round to 5. 5 4.85 60 ÷ 5 = 12 Estimate The estimate is the same as Cara’s calculation. The lobster cost about $12 per pound.

23. 4-1 Estimate with Decimals Course 2 Insert Lesson Title Here Try This: Example 3 Clem spent $18.43 on 11.7 pounds of apples. Is it reasonable to say that Clem spent about $2 per pound on apples? Round to the nearest multiple of 10. $20 18.43 10 divides evenly into 20 without a remainder. 10 11.7 20 ÷ 10 = 2 Estimate The estimate is the same as Clem’s calculation. The apples cost about $2 per pound.

24. 4-1 Estimate with Decimals Course 2 Insert Lesson Title Here Lesson Quiz: Part 1 Estimate by rounding to nearest integer. 1. 68.4 + 29.5 2. 7.24 + (–10.5) Use compatible numbers to estimate. 3. 48.27  4.67 4. 54.37  5.67 98 –4 Possible answers: 250 9