Do Now 2/15/12

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Do Now 2/15/12

• Take out HW from last night.
• 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 Modells. Sports
  Authority is offering the same basketball at 20
  off the regular price of 19.99. Estimate to
  determine which store is offering the better
  deal?

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Punchline worksheet 92

• What Were the Crash Dummys 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
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Objective

• SWBAT estimate percents

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Section 6.2 Estimating with Percents

• You can use fractions or decimals to estimate
  with percents.

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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 Modells.
Sports Authority is offering the same basketball
at 20 off the regular price of 19.99. 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
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Use a fraction and compatible numbers to estimate
the percent of each number.
Finding Percent of a Number
means multiplication
Find 25 of 35.
1 4
25
Find 34 of 63.
1 3
34
Find 8 of 261.
1 10
8
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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
4.5
.0
45
0.45
.0
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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.
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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 of 60 6 2 3
6 3 9
Add the 10 and 5 estimates.
Tim should leave about 9 for a 15 tip.
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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 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.
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Homework
NJASK7 Prep

• Text p. 238, 12-42 evens