1. Do Now 2/15/12 Take out HW from last night. Copy HW in your planner.
Punchline worksheet #92
Copy HW in your planner.
Text p. 238, #12-42 evens
In your journal, answer the following question. A basketball costs $14.99 at Modell’s. Sports Authority is offering the same basketball at 20% off the regular price of $ Estimate to determine which store is offering the better deal?

2. Punchline worksheet 92 “What Were the Crash Dummy’s Last Words?”
GIVE ME A BRAKE
“Why Did the Little Boy Wear a Sheet to Go Trick-or-Treating?”
HE WAS DRESSED UP AS A MATTRESS

3. Objective
SWBAT estimate percents

4. Section 6.2 “Estimating with Percents”
You can use fractions or decimals to estimate with percents.

5. Estimating Percents with Fractions
You can estimate the percent of a number by substituting a fraction that is close to a given percent.
Percent
10%
20%
25%
33 %
50%
66 %
Fraction
A basketball costs $14.99 at Modell’s. Sports Authority is offering the same basketball at 20% off the regular price of $ Estimate to determine which store is offering the better deal?
Find 20% of $19.99
Compatible numbers –
numbers that are close and help you
use mental math to find the solution

6. Finding Percent of a Number
means multiplication
Use a fraction and compatible numbers to estimate the percent of each number.
Find 25% of 35. 1 4
25%
Find 34% of 63. 1 3
34%
Find 8% of 261. 1 10 8%

7. Estimating Percents with Decimals
Another way to estimate percents is to find 1% or 10% of a number. You can do this by moving the decimal point in the number.
10% 1%
Find of any number by moving the decimal point 1 place to the left.
Find of any number by moving the decimal point 2 places to the left.
Find 10% of 45
Find 1% of 45 45 .0
= 4.5 45 .0
= 0.45

8. Use 1% or 10% to estimate the percent of each number.
Find 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% equals 4 · 1%.
4% of 18 is about 0.8.
Find 29% of 80
29% is about 30, so find 30% of 80.
10% of 80 = 80. .
30% of 80 = 3 · 8.0 = 24.0
30% equals 3 · 10%.
29% of 80 is about 24.

9. Real-Life Application
Tim spent $58 on dinner for his family. About how much money should he leave for a 15% tip?
Since $58 is about $60, find 15% of $60.
15% = 10% + 5%
Think: 15% is 10% + 5%.
10% of $60 = $6
5% is of 10% so divide $6 by 2. 1 2
5% of $60 = $6 ÷ 2 = $3
$6 + $3 = $9
Add the 10% and 5% estimates.
Tim should leave about $9 for a 15% tip.

10. Real-Life Application
Amanda spent $12 on a hair cut. About how much money should she leave for a 15% tip?
Since $12 is about $10, find 15% of $10.
15% = 10% + 5%
Think: 15% is 10% + 5%.
10% of $10 = $1
5% is of 10% so divide $1 by 2. 1 2
5% of $10 = $1 ÷ 2 = $0.50
$1 + $0.50 = $1.50
Add the 10% and 5% estimates.
Amanda should leave about $1.50 for a 15% tip.

11. NJASK7 Prep
Homework
Text p. 238, #12-42 evens