Subtract 42/30 from 15/21
1st number: 15/21, 2nd number: 1 12/30
15/21 - 42/30 is -24/35.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 21 and 30 is 210
Next, find the equivalent fraction of both fractional numbers with denominator 210 - For the 1st fraction, since 21 × 10 = 210,
15/21 = 15 × 10/21 × 10 = 150/210 - Likewise, for the 2nd fraction, since 30 × 7 = 210,
42/30 = 42 × 7/30 × 7 = 294/210 - Subtract the two like fractions:
150/210 - 294/210 = 150 - 294/210 = -144/210 - After reducing the fraction, the answer is -24/35
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 30/21-42/30 15/21-84/30 15/42-42/30 15/21-42/60 45/21-42/30 15/63-42/30 15/21-42/90 75/21-42/30