Subtract 81/40 from 21/70
1st number: 21/70, 2nd number: 2 1/40
21/70 - 81/40 is -69/40.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 70 and 40 is 280
Next, find the equivalent fraction of both fractional numbers with denominator 280 - For the 1st fraction, since 70 × 4 = 280,
21/70 = 21 × 4/70 × 4 = 84/280 - Likewise, for the 2nd fraction, since 40 × 7 = 280,
81/40 = 81 × 7/40 × 7 = 567/280 - Subtract the two like fractions:
84/280 - 567/280 = 84 - 567/280 = -483/280 - After reducing the fraction, the answer is -69/40
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 42/70-81/40 21/70-81/80 63/70-81/40