Rule 19:
To subtract, the denominators must be equal. You essentially following the same steps as in addition.
Build each fraction so that both denominators are equal.
Combine the numerators according to the operation of subtraction or additions.
The denominators will be the denominator of the built-up fractions.
Reduce the answer.

Problem 5:
Calculate tex2html_wrap_inline74 and reduce your answer.
The answer is tex2html_wrap_inline76 .

Convert the whole number 5 to a fraction and rewrite the problem.

tex2html_wrap_inline78 .

The denominators are different; therefore, the first step is to build the fractions to fractions with common denominators.

20 can be factored as follows: 20 = 4 tex2html_wrap_inline80 5 and 24 can be factored as follows: 24 = 4 tex2html_wrap_inline80 6.

Rewrite the fractions where the denominators are in factored form.

tex2html_wrap_inline84 .

It appears that the common denominators must have the factors 4, 5 and 6. 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_inline86 ,

tex2html_wrap_inline88 , and

tex2html_wrap_inline90 .

Combine the numerators: 600 - 18 - 5 = 577.

The answer is tex2html_wrap_inline96 .

This answer is already reduced so you can skip step 4.

You can check the answer with your calculator.

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