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.

Calculate tex2html_wrap_inline50 .
The answer is tex2html_wrap_inline52 .
The denominators are different, so you must build each fraction to a form where they both have the same denominator. Since both 2 and 3 will divide evenly into 6, build both fractions to a denominator of 6.

tex2html_wrap_inline54 and tex2html_wrap_inline56 .

tex2html_wrap_inline50 can now be written tex2html_wrap_inline60.
Combine the numerators: for the numerator in the answer.
3 - 2 = 1.
The answer is tex2html_wrap_inline64 . This answer is already reduced, so you can skip step 4.

Now prove to yourself with your calculator that your answer is correct. Calculate 1 divided by 2, calculate 1 divided by 3, and combine the results. Now divide 1 by 6. Both answers should be the same. If you are correct, the answers are the same (equivalent) and you have successfully combine two fractions using subtraction.

If you would like to review another example, click on the word Example.

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Author:Nancy Marcus

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