Subtract 21/20 from 90/70
1st number: 1 20/70, 2nd number: 1 1/20
90/70 - 21/20 is 33/140.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 70 and 20 is 140
Next, find the equivalent fraction of both fractional numbers with denominator 140 - For the 1st fraction, since 70 × 2 = 140,
90/70 = 90 × 2/70 × 2 = 180/140 - Likewise, for the 2nd fraction, since 20 × 7 = 140,
21/20 = 21 × 7/20 × 7 = 147/140 - Subtract the two like fractions:
180/140 - 147/140 = 180 - 147/140 = 33/140
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 90/70-42/20 90/70-21/40 90/70-63/20 90/70-21/60