Fractions

Subtract Fractions

Subtract 3/8 from 7/8. The denominators already match, so subtract the numerators: 7 - 3 = 4, giving 4/8. Then simplify: 4/8 = 1/2.

Example

Subtract 3/8 from 7/8, then simplify the result.

highlighted = computed this step

Step 1 — Set up

Set up the fraction expression.

78−38\frac{7}{8} - \frac{3}{8}
Start with 7/8; remove 3/87/8Plan: remove 3 of the 7 shaded pieces.All pieces are the same size: 7 shaded pieces out of 8.

Step 2 — Subtract numerators

Subtract the numerators: 7 - 3 = 4.

7−3=47 - 3 = \hl{4}
Subtract shaded pieces: 7 - 3 = 47/87 shaded pieces - 3 removed pieces = 4 shaded pieces7 shaded pieces - 3 removed pieces = 4 shaded pieces.

Step 3 — Keep denominator

Keep denominator 8; the numerator is 4.

78−38=48\frac{7}{8} - \frac{3}{8} = \hlmath{\frac{4}{8}}
The denominator stays 8 equal pieces7/84 shaded pieces out of 8 equal pieces makes 4/8The bar still has 8 equal pieces, so the raw result is 4/8.

Step 4 — Simplify

Simplify the fraction to 1/2.

48=12\frac{4}{8} = \hlmath{\frac{1}{2}}
4/8 simplifies to 1/27/84/8 = 1/2Group the remaining shaded pieces to show the same amount as 1/2.1/24/8 = 1/2

Step 5 — Result

Read the final result.

78−38=12\frac{7}{8} - \frac{3}{8} = \frac{1}{2}
7/8 - 3/8 = 1/27/87/8 - 3/8 = 1/2The value left after removing 3/8 is 1/2.1/24/8 = 1/2
subtract-and-simplify Subtracting fractions with the same denominator works just like adding: keep the denominator and subtract the numerators. Always check whether the result can be simplified by dividing both parts by their GCD.