6-3 estimate with percents course 2 warm up warm up problem of the day problem of the day lesson...
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6-3 Estimate with Percents
Course 2
Warm UpWarm Up
Problem of the DayProblem of the Day
Lesson PresentationLesson Presentation
Homework pg. 338 #11-19 and29-32Warm UpWrite each percent as a fraction and as a decimal.
1. 75% January 26, 2012
2. 10%
3. 32%
4. 17%
34
, 0.75
Course 2
6-3 Estimate with Percents
, 0.1 10 1
, 0.32 25 8
, 0.17 10017
EQ: When is the situation to use estimate of a percent or when does it need to be exact.
Course 2
6-3 Estimate with Percents
Power Point Lesson 6:3 KIN Page 147-148
Learn to estimate percents.
Course 2
6-3 Estimate with Percents
Course 2
6-3 Estimate with Percents
The table shows common percents and their fraction equivalents. You can use fractions to estimate the percent of a number by choosing a fraction that is close to a given percent.
Percent
Fraction
10% 20% 25% 50%33 %13 66 %2
3
15
14
13
12
23
110
Use a fraction to estimate 27% of 63.
Additional Example 1: Using Fractions to Estimate Percents
Course 2
6-3 Estimate with Percents
27% of 63 14
· 63
14
· 60
1527% of 63 is about 15.
Compatible numbers are close to the numbers in the problem and help you use mental math to find a solution.
Remember!
Think: 27% is about 25% and
25% is equivalent to .14
Change 63 to a compatible number.
Multiply.
Use a fraction to estimate 48% of 91.
Check It Out: Example 1
Course 2
6-3 Estimate with Percents
48% of 91 12
· 91
12
· 90
45
48% of 91 is about 45.
Think: 48% is about 50% and
50% is equivalent to .12
Change 91 to a compatible number.
Multiply.
Tara’s T’s is offering 2 T-shirts for $16, while Good-T’s is running their buy one for $9.99, get one for half price sale. Which store offers the better deal?
Additional Example 2: Consumer Math Application
Course 2
6-3 Estimate with Percents
First find the discount price for 2 t-shirts at Good T’s.
50% of $9.99 = 12
· $9.99
12
· $10
$5The second shirt cost approximately $5. Since $10 + $5 = $15, the 2 T-shirts for $15 at Good-T’s is the better deal.
Think: 50% is equivalent to .12
Change $9.99 to a compatible number.
Multiply.
Check It Out: Example 2
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Course 2
6-3 Estimate with Percents
First find the discount on the notebook at Billy’s Office Supply.
25% of $9.75 = 14
· $9.75
14
· $10
$2.50The discount is approximately $2.50. Since $10 - $2.50 = $7.50, the notebook from K’s Office Supply Store is the better deal.
Think: 25% is equivalent to .14
Change $9.75 to a compatiblenumber.
Multiply.
Billy’s Office Supply Store is offering 25% off a leather notebook, originally priced at $9.75. K’s Office Supply Store offers the same notebook, not on sale, at $7.00. Which store offers the better deal?
Use 1% or 10% to estimate the percent of each number.
Additional Example 3A: Estimating with Simple Percents
Course 2
6-3 Estimate with Percents
4% of 18
18 is about 20, so find 4% of 20.
1% of 20 = 20.
4% of 20 = 4 · 0.2 = 0.8
4% of 18 is about 0.8.
4% equals 4 · 1%.
.
Use 1% or 10% to estimate the percent of each number.
Additional Example 3B: Estimating with Simple Percents
Course 2
6-3 Estimate with Percents
29% of 80
29% is about 30, so find 30% of 80.
10% of 80 = 80.
30% of 80 = 3 · 8.0 = 24.0
29% of 80 is about 24.
30% equals 3 · 10%.
.
Use 1% or 10% to estimate the percent of each number.
Check It Out: Example 3A
Course 2
6-3 Estimate with Percents
5% of 14
14 is about 15, so find 5% of 15.
1% of 15 = 15.
5% of 15 = 5 · 0.15 = 0.75
5% of 14 is about 0.75.
5% equals 5 · 1%.
.
Tim spent $58 on dinner for his family. About how much money should he leave for a 15% tip?
Additional Example 4: Consumer Math Application
Course 2
6-3 Estimate with Percents
Since $58 is about $60, find 15% of $60.
15% = 10% + 5%
10% of $60 = $6
5% of $60 = $6 ÷ 2 = $3
$6 + $3 = $9
Tim should leave about $9 for a 15% tip.
Think: 15% is 10% + 5%.
5% is of 10% so divide $6 by 2.
12
Add the 10% and 5% estimates.
Amanda spent $12 on a hair cut. About how much money should she leave for a 15% tip?
Check It Out: Example 4
Course 2
6-3 Estimate with Percents
Since $12 is about $10, find 15% of $10.
15% = 10% + 5%
10% of $10 = $1
5% of $10 = $1 ÷ 2 = $0.50
$1 + $0.50 = $1.50
Amanda should leave about $1.50 for a 15% tip.
Think: 15% is 10% + 5%.
5% is of 10% so divide $1 by 2.
12
Add the 10% and 5% estimates.
Lesson Quiz1. Use a fraction to estimate 48% of 72.
2. A café is offering 10% off the $4.99 lunch. If a diner is offering the same lunch for $4.59, which is offering the better deal?
Estimate the percent of each number.
3. 4% of 220
4. 19% of 75
5. Mr. and Mrs. Dargen spend $46.25 on a meal. About how much should they leave for a 15% tip?
The café
36
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8.8
15
Course 2
6-3 Estimate with Percents
$7