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6.3 Students will be able to use estimates to solve percent problems. Daily Quiz Green 1.I went out to eat and spent How much would I spend on tip if the service was excellent? Blue 1.I went out to eat and spent $ How much would I spend on the whole meal (including tip), if the service was good. Red 1. I went out to eat and spent How much would I spend on the whole meal (including tip), if the service was poor. $6.00 $75.48 $33.73
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6.3 Students will be able to use estimates to solve percent problems.
Es t ima t eEs t ima te Es t ima t e Es t ima t e
Warm Up
1. What is 23% of 24?2. What number is 85% of 103?3. What percent of 23 is 9?4. 42% of what number is 28?
5. Solve for x. 5x = 246. I went out to eat and spent $24.38. How
much did I spend in tip if the service was excellent?How much would the whole meal cost?
5.52 87.55
39% 66.7
X = 4.8
$4.00 or $5.00 $28.38 or $29.38
6.3 Students will be able to use estimates to solve percent problems.
Es t ima t eEs t ima te Es t ima t e Es t ima t e
An estimate is a useful answer that is close to the exact answer.
6.3 Students will be able to use estimates to solve percent problems.
Es t ima t eEs t ima te Es t ima t e Es t ima t e
Daily Quiz
Green1. I went out to eat and spent 32.85. How much would I
spend on tip if the service was excellent?
Blue2. I went out to eat and spent $63.48. How much would I
spend on the whole meal (including tip), if the service was good.
Red1. I went out to eat and spent 29.23. How much would I
spend on the whole meal (including tip), if the service was poor.
$6.00
$75.48
$33.73
6.3 Students will be able to use estimates to solve percent problems.
Es t ima t eEs t ima te Es t ima t e Es t ima t e
Benchmark: 10%(Estimate)What is 10% of 20?
What is 10% of 30?
What is 10% of 89.83?
What is 10% of 59.28?
What is 10% of 28.39?
2
3
9
6
3
If we move the decimal
once to the left for 10%,
how do we find 30%?
What is 30% of 25?
What is 30% of 35?
What is 30% of 89.83?
What is 30% of 59.28?
What is 30% of 28.39?
6
9
27
18
9
Benchmark: 30%
6.3 Students will be able to use estimates to solve percent problems.
Es t ima t eEs t ima te Es t ima t e Es t ima t e
Estimate.21% of 66
Estimating with Percents
21% ≈ 20% Use a benchmark close to 21%. 66 ≈ 65 Use compatible numbers.
So 21% of 66 is about 13.
10% of 65 = 6.5 Use the benchmark percents to find 10%
20% of 65 = 13 Double to find 20%
6.3 Students will be able to use estimates to solve percent problems.
Es t ima t eEs t ima te Es t ima t e Es t ima t e
Estimate.29% of 86
Try It
29% ≈ 30% Use a benchmark close to 29%. 86 ≈ 90 Use compatible numbers
10% of 90 = 9 Find 10%
So 29% of 86 is about 27.
30% of 90 = 9(3) = 27 Multiply 10% by 3
6.3 Students will be able to use estimates to solve percent problems.
Es t ima t eEs t ima te Es t ima t e Es t ima t e
Estimate.36% of 120
Estimating with Percents
Instead of computing the exact answer of 36% 120, estimate.36% 35% Round.
30% + 5% Break down the percent into smaller parts.
12 Find 10% 36 Multiply by 3 to get 30%
Divide 10% by 2 to get 5% 636 + 6 = 42 Add 30% and 5%
6.3 Students will be able to use estimates to solve percent problems.
Es t ima t eEs t ima te Es t ima t e Es t ima t e
Estimate.44% of 131
Estimating with Percents
Instead of computing the exact answer of 44% 141, estimate.44% 45% Round.
40% + 5% Break down the percent into smaller parts.
14 Find 10% 42 Multiply by 3 to get 30%
Divide 10% by 2 to get 5% 742 + 7 = 49 Add 30% and 5%
6.3 Students will be able to use estimates to solve percent problems.
Es t ima t eEs t ima te Es t ima t e Es t ima t e
What percent is:1 out of 250%
3 out of 475%
80 out of 20040%
13 out of 13100%
400 out of 100040%
5 out of 5001%
Bench
marks
6.3 Students will be able to use estimates to solve percent problems.
Es t ima t eEs t ima te Es t ima t e Es t ima t e
Estimate each percent
1.82 out of 205
2.33 out of 42
3.82 out of 159
4.302 out of 998
5.219 out of 222
40%
75%
50%
30%
100%
6.3 Students will be able to use estimates to solve percent problems.
Es t ima t eEs t ima te Es t ima t e Es t ima t e
Try ItA clothing company has determined that approximately 9% of the sheets it makes are irregular. Out of a shipment of 4073, the company manager estimates that 397 sheets are irregular. Estimate to see if the manager’s number is reasonable. Explain.
9% 4073 ≈ 10% 4000 Use compatible numbers.
≈ 0.10 4000 Write 10% as a decimal.
Multiply. ≈ 400Because 397 is close to 400, the manager’s number is reasonable.
6.3 Students will be able to use estimates to solve percent problems.
Es t ima t eEs t ima te Es t ima t e Es t ima t e
Lesson Quiz: Part IEstimate.
1. 34% of 12 2. 113% of 803. Ian had dinner with some friends at a
restaurant. His food and drink cost $10.25. If the sales tax is 8.25% and he wants to leave a 20% tip, about how much should Ian pay?
4
90
$13.00
Possible answers:
6.3 Students will be able to use estimates to solve percent problems.
Es t ima t eEs t ima te Es t ima t e Es t ima t e
Lesson Quiz: Part II
4. Approximately 8% of each batch of jeans produced at one factory is defective. Ms. Fleming said that in a batch of 400 jeans, about 35 jeans would be defective. Estimate to determine if her number is reasonable. Explain.
Yes, it is reasonable because 8% of 400 is a little less than 10% of 400. 10% of 400 is 40, and 35 is a little less than 40.
6.3 Students will be able to use estimates to solve percent problems.
Es t ima t eEs t ima te Es t ima t e Es t ima t e
1. Estimate.26% of 35
A. 8
B. 9
C. 17
D. 26
Lesson Quiz for Student Response Systems
6.3 Students will be able to use estimates to solve percent problems.
Es t ima t eEs t ima te Es t ima t e Es t ima t e
2. Smith bought a book at an online store. The cost of the book was $12.25. If the sales tax rate is 7.75% and the shipping charges are 10% of the cost of the book, about how much should he pay?
A. $13.14
B. $14.42
C. $15.25
D. $16.50
Lesson Quiz for Student Response Systems
6.3 Students will be able to use estimates to solve percent problems.
Es t ima t eEs t ima te Es t ima t e Es t ima t e
3. On an average 9% of the CDs produced by a company are defective. The Quality Control Manager states that out of 1300 CDs produced, 121 are defective. Estimate to determine if his number is reasonable. Explain.
A. yes; because 9% of 1300 is a little less than 10% of 1300. 10% of 1300 is 130 and 121 is a little less than 130.
B. no: because 9% of 1300 is a little greater than 10% of 1300. 10% of 1300 is 130 which is greater than 121.
Lesson Quiz for Student Response Systems
