Transcript Do Now 11/14/11

Do Now 11/15/11

Take out your HW from last night.


Copy HW in your planner.


Text p. 102, #10-40 evens, #42, 43, 48, & 49
Text p. 106, #10-44 evens
In your journal, estimate an answer to the
following situation. Potato salad costs $0.99 per
pound at the deli counter. About how much do
you think 6.5 pounds of potato salad will cost?
Homework
Text p. 102, #10-40 evens, #42, 43, 48, & 49










10) 39.05
12) 16.917
14) 15.33
16) 9.071
18) 2.24
20) 12.79
22) 4.47
24) 31.15
26) 8.25 minutes
28) -0.338










30) -17.361
32) -125.55
34) 48.46
36) 30.623
38) -2.6
40) 1,642.5 miles
42) 1.6 °F
43) 1915
48) B
49) G
Objective

SWBAT multiply decimals
Section 3-2
Multiplying Decimals
To multiply decimals, multiply as you would
integers. To place the decimal point in the
product count the number of decimal places in
each factor. The product will have the same
number of decimal places as the sum of the
decimal places in the factors.
Find the product.
3.06
x 1.4
1224
+3060
4284
4.284
3.06 x 1.4
2 decimal places
1 decimal place
How many
decimal places
are in
each number?
How many
decimal places
are in the sum of
both numbers?
3 decimal places will then be in the product!
Do you see a pattern?
How many decimal places
are in the factors?
12
x4
48
1.2
x 4
4.8
How many decimal places
are in the products?
0.12
x 0.4
48
000
0.048
Practice

1) 1.46 x 0.02
1)
1.46
x 0.02
0.0292

2) 3.04 x 1.6
2)
3.04
x 1.6
1824
_+3040
4.864
“Multiplying Integers”
Rule #1
The product of two integers with the same
sign is always POSITIVE!
8 x 3 = 24
-8 · (-7) = 56
Rule #2
The product of two integers with different
signs is always NEGATIVE!
-6 x 3 = -18
8(-4) = -32
Estimating
Round each decimal to the nearest integer than
find the product.
7.2(-4.36)
-28
-3.3(-3.3)
9
-11.3 x 7.76
-88
-7.3(-6.72)
49
Find the product.
-2.78
x 0.8
-2.224
-2224
-2.78 · 0.8
2 decimal places
1 decimal place
How many
decimal places
are in
each number?
How many
decimal places
are in the sum of
both numbers?
3 decimal places will then be in the product!
Find the product.
0.014
x -16
0084
+0140
-0.224
-0224
-16 x 0.014
3 decimal places
0 decimal places
How many
decimal places
are in
each number?
How many
decimal places
are in the sum of
both numbers?
3 decimal places will then be in the product!
“Real-Life”
On average, Americans eat 0.25 lb of peanut
butter per month. How many pounds of peanut
butter are eaten by approximately 302 million
Americans living in the United States per month?
302
x 0.25
1510
6040
75.50
million pounds of peanut butter are
eaten by Americans each month
24
Homework
Text p. 106, #10-44 evens