Answers

Subtract 70/45 from 81/80

1^st number: 1 1/80, 2^nd number: 1 25/45

81/80 - 70/45 is -391/720.

Steps for subtracting fractions

1. Find the least common denominator or LCM of the two denominators:
   LCM of 80 and 45 is 720
   
   Next, find the equivalent fraction of both fractional numbers with denominator 720
2. For the 1st fraction, since 80 × 9 = 720,
   81/80 = 81 × 9/80 × 9 = 729/720
3. Likewise, for the 2nd fraction, since 45 × 16 = 720,
   70/45 = 70 × 16/45 × 16 = 1120/720
4. Subtract the two like fractions:
   729/720 - 1120/720 = 729 - 1120/720 = -391/720

MathStep (Works offline)

Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad

Related: ⁸¹/₈₀-⁷⁰/₉₀

Subtract Fractions Calculator