Knowing how to add and subtract decimals is important in life. For
example, when you handle money at a shop, the bank or post office, you
should use your knowledge of decimals to calculate the money and any change
exchanged.
Addition of Decimals
To add decimal numbers, insert zeros in empty decimal place values so that all of the numbers
have the same number of decimal places and write the numbers such that their
decimal
points are below one another.
Example 7
Calculate 5.84 + 8 + 12.79.
Solution:
Note:
The decimal point in the answer is lined up with the decimal points in
the numbers set out vertically.
Subtraction of Decimals
To subtract a small decimal number from a larger decimal number, write
them down with the larger one on top and the decimal points underneath one
another. Then calculate the subtraction as you would for whole numbers
and line up the decimal point in the answer.
Example 8
Rewrite 3.67 – 1.83 in columns and then calculate.
Solution:
Example 9
Rewrite 83.47 – 57.684 in columns and then calculate.
Solution:
Note:
To add (or subtract) decimals, always fill empty place values with zeros
so that all of the numbers have the same number of decimal places.
Example 10
Rewrite 24 – 8.327 in columns and then calculate.
Solution:
Note:
24 = 24.000
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