Rule 18:
To add fractions, the denominators must be equal. Complete the following steps to add two fractions.
1.
Build each fraction so that both denominators are equal.
2.
Add the numerators of the fractions.
3.
The denominators will be the denominator of the built-up fractions.
4.

Problem 2:
Solution:
The denominators are different, so you must build each fraction to a form where they both have the same denominator. Since both 5 and 15 will divide evenly into 15, build both fractions to a denominator of 15. Build the fraction to an equivalent fraction whose denominator is 15.

.

can now be written .

4 + 9 = 13. Add the fractions to get .

Check:
Now prove to yourself with your calculator that your answer is correct. Calculate 4 divided by 15, 3 divided by 5, and add the results. Now divide 13 by 15. 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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