Fractions Subtraction: Simple Fractions, Common Denominator

On this page and the next page, we will subtract fractions that already have a common denominator.

To subtract two fractions, we:
1) Make sure that each fraction has the same denominator: the least common denominator.
2) Subtract only the top part (numerator) of each fraction.
3) After subtracting, write the answer over the denominator.

Our first example is 3 / 5 - 1 / 5:

1) Each fraction has the same denominator: 5.

2) 3 - 1 = 2.

3) 2 over 5 is 2/5. That wasn't hard, was it?

3 / 5
-
1 / 5
=
2 / 5
-
=
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The next example is 5 / 9 - 4 / 9:

1) Each fraction has the same denominator: 9.

2) 5 - 4 = 1.

3) 1 over 9 is 1 / 9.

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5 / 9
-
4 / 9
=
1 / 9
-
=
White Box   White Box   White Box   White Box   White Box   White Box   White Box   White Box  plus     White Box   White Box   White Box   White Box   White Box   White Box   White Box   White Box  equals