Subtract 21/15 from 42/70
1st number: 42/70, 2nd number: 1 6/15
42/70 - 21/15 is -4/5.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 70 and 15 is 210
Next, find the equivalent fraction of both fractional numbers with denominator 210 - For the 1st fraction, since 70 × 3 = 210,
42/70 = 42 × 3/70 × 3 = 126/210 - Likewise, for the 2nd fraction, since 15 × 14 = 210,
21/15 = 21 × 14/15 × 14 = 294/210 - Subtract the two like fractions:
126/210 - 294/210 = 126 - 294/210 = -168/210 - After reducing the fraction, the answer is -4/5
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 84/70-21/15 42/70-42/15 42/70-21/30 42/70-63/15 42/70-21/45 42/70-21/75