Answers

Subtract 90/84 from 70/81

1^st number: 70/81, 2^nd number: 1 6/84

70/81 - 90/84 is -235/1134.

Steps for subtracting fractions

1. Find the least common denominator or LCM of the two denominators:
   LCM of 81 and 84 is 2268
   
   Next, find the equivalent fraction of both fractional numbers with denominator 2268
2. For the 1st fraction, since 81 × 28 = 2268,
   70/81 = 70 × 28/81 × 28 = 1960/2268
3. Likewise, for the 2nd fraction, since 84 × 27 = 2268,
   90/84 = 90 × 27/84 × 27 = 2430/2268
4. Subtract the two like fractions:
   1960/2268 - 2430/2268 = 1960 - 2430/2268 = -470/2268
5. After reducing the fraction, the answer is -235/1134

MathStep (Works offline)

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

Related:

Subtract Fractions Calculator