SUBTRACTION: Example 4

Rule 19:

To subtract, the denominators must be equal. You essentially following the same steps as in addition.

1.: Build each fraction so that both denominators are equal.
2.: Combine the numerators according to the operation of subtraction or additions.
3.: The denominators will be the denominator of the built-up fractions.
4.: Reduce the answer.

Example:

Calculate

Answer:

The answer is

Solution:

The denominators are different; therefore, the first step is to build the fractions to fractions with common denominators. 24 can be factored as follows: 24 = 4

6 = 2

3 and 36 can be factored as follows: 36 = 4

9 = 2

3.
Rewrite both fractions where the denominators are in factored form.

tex2html_wrap_inline68 .

Multiply each fraction by the form of 1 that will yield denominators with the same set of factors. (i.e., you can find each set of factors in the denominator of the answer)

tex2html_wrap_inline27

Combine the numerator: 15 - 14 = 1. The answer is tex2html_wrap_inline74 .
This answer is already reduced.

Check:

Now prove to yourself with your calculator that your answer is correct. Calculate 5 divided by 24, 7 divided by 36, and combine the answers.. Now divide 1 by 72. Both answers should be the same. If you are correct, the answers are the same (equivalent) and you have successfully added two fractions.

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Author:Nancy Marcus