Subtract 7/8 from 30/21
1st number: 1 9/21, 2nd number: 7/8
30/21 - 7/8 is 31/56.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 21 and 8 is 168
Next, find the equivalent fraction of both fractional numbers with denominator 168 - For the 1st fraction, since 21 × 8 = 168,
30/21 = 30 × 8/21 × 8 = 240/168 - Likewise, for the 2nd fraction, since 8 × 21 = 168,
7/8 = 7 × 21/8 × 21 = 147/168 - Subtract the two like fractions:
240/168 - 147/168 = 240 - 147/168 = 93/168 - After reducing the fraction, the answer is 31/56
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 60/21-7/8 30/21-14/8 30/42-7/8 30/21-7/16 90/21-7/8 30/21-21/8 30/63-7/8 30/21-7/24 30/21-35/8 30/21-7/40 30/21-49/8 30/21-7/56