Subtract 21/49 from 20/42
20/42 - 21/49 is 1/21.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 42 and 49 is 294
Next, find the equivalent fraction of both fractional numbers with denominator 294 - For the 1st fraction, since 42 × 7 = 294,
20/42 = 20 × 7/42 × 7 = 140/294 - Likewise, for the 2nd fraction, since 49 × 6 = 294,
21/49 = 21 × 6/49 × 6 = 126/294 - Subtract the two like fractions:
140/294 - 126/294 = 140 - 126/294 = 14/294 - After reducing the fraction, the answer is 1/21
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 40/42-21/49 20/42-42/49 20/84-21/49 20/42-21/98 60/42-21/49 20/42-63/49