Subtract 20/21 from 9/28
9/28 - 20/21 is -53/84.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 28 and 21 is 84
Next, find the equivalent fraction of both fractional numbers with denominator 84 - For the 1st fraction, since 28 × 3 = 84,
9/28 = 9 × 3/28 × 3 = 27/84 - Likewise, for the 2nd fraction, since 21 × 4 = 84,
20/21 = 20 × 4/21 × 4 = 80/84 - Subtract the two like fractions:
27/84 - 80/84 = 27 - 80/84 = -53/84
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 18/28-20/21 9/28-40/21 9/56-20/21 9/28-20/42 27/28-20/21 9/28-60/21 9/84-20/21 9/28-20/63 45/28-20/21 63/28-20/21