Subtract 72/21 from 1/8
1st number: 1/8, 2nd number: 3 9/21
1/8 - 72/21 is -185/56.
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,
1/8 = 1 × 21/8 × 21 = 21/168 - Likewise, for the 2nd fraction, since 21 × 8 = 168,
72/21 = 72 × 8/21 × 8 = 576/168 - Subtract the two like fractions:
21/168 - 576/168 = 21 - 576/168 = -555/168 - After reducing the fraction, the answer is -185/56
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 2/8-72/21 1/16-72/21 1/8-72/42 3/8-72/21 1/24-72/21 1/8-72/63 5/8-72/21 1/40-72/21 7/8-72/21 1/56-72/21