Subtract 42/21 from 2/8
1st number: 2/8, 2nd number: 2 0/21
2/8 - 42/21 is -7/4.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 8 and 21 is 168
Next, find the equivalent fraction of both fractional numbers with denominator 168 - For the 1st fraction, since 8 × 21 = 168,
2/8 = 2 × 21/8 × 21 = 42/168 - Likewise, for the 2nd fraction, since 21 × 8 = 168,
42/21 = 42 × 8/21 × 8 = 336/168 - Subtract the two like fractions:
42/168 - 336/168 = 42 - 336/168 = -294/168 - After reducing the fraction, the answer is -7/4
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 4/8-42/21 2/8-84/21 2/16-42/21 6/8-42/21 2/24-42/21 2/8-42/63 10/8-42/21 2/40-42/21 14/8-42/21 2/56-42/21