WORKING WITH DECIMALS
ADDING & SUBTRACTING DECIMALS
Rules:
 Always remember to line up the decimals when setting up the problem.
 Add zeros to hold place value if needed.
 Bring down the decimal point into your answer.
Example:
 Set up the problem so the decimals are lined up
25.8
- 14.62
25.8
+ 14.62
 Add zeros where necessary so all places are full
25.80
- 14.62
25.80
+ 14.62
 Add or Subtract
7
1 1
10
25.80
- 14.62
1 1 18
25.80
+ 14.62
40 42
 Bring down the decimal point
7
1 1
10
25.80
- 14.62
11.18
25.80
+ 14.62
40. 42
MULTIPLING DECIMALS
 Set up the problem
2.3 4
x 2.1
 Multiply normally (Do not forget your place holders)
7
2.3 4
x 2.1
234
+ 468X
4 914
 Look at the original problem and count the number of places after each decimal
point
2.3 4 -- 2 numbers after the decimal point
x 2.1 -- 1 number after the decimal point
*in this problem there are 3 total numbers after the decimal point
 Move the decimal point in your answer over that number of places
4
.914
.3
2
1
DIVIDING DECIMALS
 Set up the problem
_______
2.5 12.5
 You cannot have a decimal outside of your “house” so you need to move the decimal
to make it a whole number.
_______
2.5 12.5
*your new problem is
25 12.5
Move decimal over 1 place
 Since you moved the decimal place over outside the “house” you need to also move it
on the inside the same amount of spaces to keep a good balance!!
_______
25. 12.5
*your new problem is
25. 125.
Move decimal over 1 place inside also
 Bring up the decimal point
____.____
25 125.
 Divide normally
__ 5.
25 125.
Your answer is 5 or 5.0