SUBTRACTION: Example 2

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, so you must build each fraction to a form where they both have the same denominator. Since both 4 and 6 will divide evenly into 12, build both fractions to a denominator of 12.

tex2html_wrap_inline54 and tex2html_wrap_inline56 .

can now be written tex2html_wrap_inline60 .
Combine the numerators: 9 - 2 = 7.
The answer is tex2html_wrap_inline64 .
This answer is already reduced, so you can skip step 4.

Check:

Now prove to yourself with your calculator that your answer is correct. Calculate 3 divided by 4, calculate 1 divided by 6, and combine the results. Now divide 7 by 12. 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