Decimal Rule
Addition of Decimals
Subtraction of Decimals
Rounding Decimals
Multiplying and Dividing Decimals
100
How do you add decimals?
You line up the decimals and then add the numbers.
100
58.9 + 3.04 =
61.94
100
3.95 - 2.7 =
1.25
100

Round to the nearest whole: 1.983

2

100

6857 x 100

685700

200
How do you subtract decimals?
You line up the decimals and then subtract the numbers.
200
.004 + 5.1 =
5.104
200
95.29 - 1.3 =
93.99
200

Round to the nearest tenth: 1.28

1.3

200

0.563 x 100

56.3

300
What do you do if there are not enough digits in the top number to subtract a problem?
You have to add on zero's.
300
.9843 + 2.67 =
3.6543
300
125 - .68 =
124.32
300

Round to the nearest hundredth: 3.782

3.78

300

24.5 ÷ 10

2.45

400

What do you do when multiplying a decimal by 10, 100, 1000 and 10 000?

Move the decimal to the right by the amount of zeros

400
5 + 2.78 + .030 =
7.81
400
.468 - .059 =
.409
400

Round to the nearest hundredth: 0.829

0.83

400

6.87 ÷ 1000

.00687

500

What do you do when dividing a decimal by 10, 100, 1000 and 10 000?

Move the decimal to the right by the amount of zeros

500
8.07 + .0976 + 23.3 + 48 =
79.4676
500
5.45 - 3.799 =
1.651
500

Round to the nearest hundredth:6.799

6.80

500

48 x 0.001

0.048

M
e
n
u