Decimal Rule
Addition of Decimals
Subtraction of Decimals
Multiplication of Decimals
Division of Decimals
Application
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
.6 x 2.1 =
1.26
100
.25 divided by .05 =
5
100

Ko has $7.50 and buys food from McDonalds for $4.99. If tax is not charged how much does he have left?

What is $2.51 left?

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
4.25 x 21 =
89.25
200
3.87 divided by .9 =
4.3
200

Eric has $8.43, Josefina has $2 and Nahio has $3.11. How much money do they have combined?

What is $13.54 combined?

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
.03 x .03 =
.0009
300
.425 divided by .005 =
85
300

Emily runs a mile in 6.5 minutes. How many miles can she run in 39 minutes?

What is 6 miles?

400
How do you multiply decimals?
You multiply the numbers and then you count how many spaces there are to the right of the decimals and count them over to the left in the answer.
400
5 + 2.78 + .030 =
7.81
400
.468 - .059 =
.409
400
2.003 x .05 =
.10015
400
.848 divided by 8 =
.106
400

Candy costs $0.50 per pound. How much will Ms. Wright spend on 4.1 pounds?

What is $2.05?

500
How do you divide decimals?
You have to get rid of the decimals on the outside by moving the decimals on the inside. Then bring the decimal straight up and divide normally.
500
8.07 + .0976 + 23.3 + 48 =
79.4676
500
5.45 - 3.799 =
1.651
500
.312 x 1.67 =
.52104
500
.4564 divided by .04
11.41
500

Brandon has $20. He buys chocolate for $3.50, popcorn for $4.25, and a soda for $3.75. How much money, if any, does he have left?

What is $8.50?

M
e
n
u