Subtract 70/16 from 21/42
1st number: 21/42, 2nd number: 4 6/16
21/42 - 70/16 is -31/8.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 42 and 16 is 336
Next, find the equivalent fraction of both fractional numbers with denominator 336 - For the 1st fraction, since 42 × 8 = 336,
21/42 = 21 × 8/42 × 8 = 168/336 - Likewise, for the 2nd fraction, since 16 × 21 = 336,
70/16 = 70 × 21/16 × 21 = 1470/336 - Subtract the two like fractions:
168/336 - 1470/336 = 168 - 1470/336 = -1302/336 - After reducing the fraction, the answer is -31/8
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 21/84-70/16 21/42-70/32 63/42-70/16 21/42-70/48 21/42-70/80