1. Add, Subtract, Multiply, and Divide Decimals
SWBAT add and subtract positive and negative decimals; multiply positive and negative decimals; divide positive and negative decimals

2. Add and Subtract Decimals
How do you add and subtract positive and negative integers?
4 + 7 = 11
= -11
= 3
What is the most important thing to remember when adding and subtracting decimals?
You MUST align the decimal points!!!

3. Examples 410.3 + (-18.01) -17.6 – 2.98 0.44 – 0.87 -2.4 – (-5.6)

4. Try the problems on your paper
-1.3
-13.1
8.87
7.9091

5. Multiplying Decimals
What sign does your answer have when you multiply the following:
Positive x Positive = Positive
Negative x Negative = Positive
Negative x Positive = Negative
How do you determine how many decimal places should go in your answer when multiplying two decimals?
Count the decimal places of the numbers you are multiplying, your answer should have the same number.

6. Examples
0.0375(-2)
(-5.01)(3)
(0.205)(-2)
-6.15(0.45)
3.2( )

7. Try the problems on your paper
0.0338
0.04
-2.259
20.5
7.2

8. Dividing Decimals
What sign does your answer have when you divide the following:
Positive x Positive = Positive
Negative x Negative = Positive
Negative x Positive = Negative
How do you determine where the decimal should go in your answer when dividing decimals?
It goes directly above the decimal in the dividend. If there is a decimal in the divisor, move it to make a whole number and then move the decimal the same number of places in the dividend.

9. Examples
31.62 ÷ -9.57 ÷
÷ 0.23
6.19 ÷ 35

10. Try the problems on your paper
12.45
-0.025
170