Subtract 3/8 from 15/21
15/21 - 3/8 is 19/56.
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,
15/21 = 15 × 8/21 × 8 = 120/168 - Likewise, for the 2nd fraction, since 8 × 21 = 168,
3/8 = 3 × 21/8 × 21 = 63/168 - Subtract the two like fractions:
120/168 - 63/168 = 120 - 63/168 = 57/168 - After reducing the fraction, the answer is 19/56
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 30/21-3/8 15/21-6/8 15/42-3/8 15/21-3/16 45/21-3/8 15/21-9/8 15/63-3/8 15/21-3/24 75/21-3/8 15/21-15/8 15/21-3/40 15/21-21/8 15/21-3/56