freeCodeCamp/guide/english/mathematics/subtracting-fractions/index.md

title
Subtracting Fractions

Subtracting Fractions

Subtracting fractions is a bit of a misnomer, as

(a/b) - (c/d) = (a/b) + (-c/d),

so there is nothing special going on here, it is just the usual addition of fractions. Namely,

(a/b) - (c/d) = (a/b) + (-c/d) = (a*d - b*c)/(d*b).

For example,

1/7 - 3/8 = (1*8 - 7*3)/(7*8) = -13/56.