Do Now 11/15/11Do Now 11/15/11 Take out your HW from last night.Take out your HW from last night.

Text p. 102, #10-40 evens, #42, 43, 48, & 49Text p. 102, #10-40 evens, #42, 43, 48, & 49

Copy HW in your planner.Copy HW in your planner. Text p. 106, #10-44 evensText p. 106, #10-44 evens

In your journal, estimate an answer to In your journal, estimate an answer to the following situation. Potato salad the following situation. Potato salad costs $0.99 per pound at the deli costs $0.99 per pound at the deli counter. About how much do you think counter. About how much do you think 6.5 pounds of potato salad will cost?6.5 pounds of potato salad will cost?

HomeworkHomework Text p. 102, #10-40 evens, #42, Text p. 102, #10-40 evens, #42,

43, 48, & 4943, 48, & 49 10) 39.0510) 39.05 12) 16.91712) 16.917 14) 15.3314) 15.33 16) 9.07116) 9.071 18) 2.2418) 2.24 20) 12.7920) 12.79 22) 4.4722) 4.47 24) 31.1524) 31.15 26) 8.25 minutes26) 8.25 minutes 28) -0.33828) -0.338

30) -17.36130) -17.361 32) -125.5532) -125.55 34) 48.4634) 48.46 36) 30.62336) 30.623 38) -2.638) -2.6 40) 1,642.5 miles40) 1,642.5 miles 42) 1.6 °F42) 1.6 °F 43) 191543) 1915 48) B48) B 49) G49) G

ObjectiveObjective

SWBAT multiply decimalsSWBAT multiply decimals

To multiply decimals, multiply To multiply decimals, multiply as you would integers. To place the as you would integers. To place the decimal point in the product count decimal point in the product count the number of decimal places in the number of decimal places in each factor. The product will have each factor. The product will have the same number of decimal places the same number of decimal places as the sum of the decimal places in as the sum of the decimal places in the factors.the factors.

Section 3-2Section 3-2Multiplying DecimalsMultiplying Decimals

Find the product. 3.06 x 1.4Find the product. 3.06 x 1.4

3.3.0606

12241224 x 1.x 1.44

How many How many decimal places decimal places are in are in each number? each number?

2 decimal places2 decimal places

1 decimal place1 decimal place

+3060+306042844284

How many How many decimal places decimal places are in the sum ofare in the sum ofboth numbers? both numbers?

3 decimal places will then be in the product!3 decimal places will then be in the product!4.4.284284

1212

4848x 4x 4

1.21.2

4.84.8 x 4x 4

0.120.12

4848 x 0.4x 0.4

0000000.0480.048

How many decimal places are in the factors?

Do you see a pattern?Do you see a pattern?

How many decimal places are in the products?

PracticePractice 1) 1.46 x 0.021) 1.46 x 0.02

2) 3.04 x 1.62) 3.04 x 1.6

1)1) 1.1.4646

x 0.x 0.0202

0.0.02920292

2)2) 3.3.0404

x 1.x 1.66

18241824

_+3040 _+3040

4.4.864864

““Multiplying Integers”Multiplying Integers”Rule #1Rule #1 The product of two integers with the The product of two integers with the

same sign is always POSITIVE!same sign is always POSITIVE!8 x 3 = 24 -8 · (-7) = 568 x 3 = 24 -8 · (-7) = 56

Rule #2Rule #2 The product of two integers with The product of two integers with

different signs is always NEGATIVE!different signs is always NEGATIVE! -6 x 3 = -18 8(-4) = -32-6 x 3 = -18 8(-4) = -32

Remember this?

EstimatingEstimatingRound each decimal to the nearest Round each decimal to the nearest

integer than find the product.integer than find the product.

7.2(-4.36)7.2(-4.36)-28-28

-11.3 x 7.76-11.3 x 7.76-88-88

-3.3(-3.3)-3.3(-3.3)99

-7.3(-6.72)-7.3(-6.72)4949

Find the product. -2.78 · 0.8Find the product. -2.78 · 0.8

-2.-2.7878 x 0.x 0.88

How many How many decimal places decimal places are in are in each number? each number?

2 decimal places2 decimal places

1 decimal place1 decimal place

-2224-2224 How many How many decimal places decimal places are in the sum ofare in the sum ofboth numbers? both numbers?

3 decimal places will then be in the product!3 decimal places will then be in the product!

-2.-2.224224

Find the product. -16 x 0.014Find the product. -16 x 0.014

0.0.014014

00840084x -16x -16

How many How many decimal places decimal places are in are in each number? each number?

3 decimal places3 decimal places

0 decimal places0 decimal places

+0140+0140-0224-0224

How many How many decimal places decimal places are in the sum ofare in the sum ofboth numbers? both numbers?

3 decimal places will then be in the product!3 decimal places will then be in the product!-0.-0.224224

““Real-Life”Real-Life”On average, Americans eat 0.25 On average, Americans eat 0.25

lb of peanut butter per month. How lb of peanut butter per month. How many pounds of peanut butter are many pounds of peanut butter are eaten by approximately 302 million eaten by approximately 302 million Americans living in the United States Americans living in the United States per month? per month?

302302x 0.25x 0.25

75.5075.50 million pounds of peanut million pounds of peanut butter are eaten by Americans butter are eaten by Americans each montheach month

15101510 60406040

2424

HomeworkHomeworkText p. 106, #10-44 evensText p. 106, #10-44 evens