Subtract 20/30 from 4/21
4/21 - 20/30 is -10/21.
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,
4/21 = 4 × 10/21 × 10 = 40/210 - Likewise, for the 2nd fraction, since 30 × 7 = 210,
20/30 = 20 × 7/30 × 7 = 140/210 - Subtract the two like fractions:
40/210 - 140/210 = 40 - 140/210 = -100/210 - After reducing the fraction, the answer is -10/21
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 8/21-20/30 4/21-40/30 4/42-20/30 4/21-20/60 12/21-20/30 4/21-60/30 4/63-20/30 4/21-20/90 20/21-20/30 28/21-20/30