Subtract 70/90 from 20/28
20/28 - 70/90 is -4/63.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 28 and 90 is 1260
Next, find the equivalent fraction of both fractional numbers with denominator 1260 - For the 1st fraction, since 28 × 45 = 1260,
20/28 = 20 × 45/28 × 45 = 900/1260 - Likewise, for the 2nd fraction, since 90 × 14 = 1260,
70/90 = 70 × 14/90 × 14 = 980/1260 - Subtract the two like fractions:
900/1260 - 980/1260 = 900 - 980/1260 = -80/1260 - After reducing the fraction, the answer is -4/63
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 40/28-70/90 20/56-70/90 60/28-70/90 20/84-70/90