Subtract 70/20 from 21/72
1st number: 21/72, 2nd number: 3 10/20
21/72 - 70/20 is -77/24.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 72 and 20 is 360
Next, find the equivalent fraction of both fractional numbers with denominator 360 - For the 1st fraction, since 72 × 5 = 360,
21/72 = 21 × 5/72 × 5 = 105/360 - Likewise, for the 2nd fraction, since 20 × 18 = 360,
70/20 = 70 × 18/20 × 18 = 1260/360 - Subtract the two like fractions:
105/360 - 1260/360 = 105 - 1260/360 = -1155/360 - After reducing the fraction, the answer is -77/24
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 42/72-70/20 21/72-70/40 63/72-70/20 21/72-70/60