# Do Now 2/15/12 Take out HW from last night. Copy HW in your planner.

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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?

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

Objective SWBAT estimate percents

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

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

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%

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

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.

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.

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.

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

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