Subtract 30/70 from 3/21
3/21 - 30/70 is -2/7.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 21 and 70 is 210
Next, find the equivalent fraction of both fractional numbers with denominator 210 - For the 1st fraction, since 21 × 10 = 210,
3/21 = 3 × 10/21 × 10 = 30/210 - Likewise, for the 2nd fraction, since 70 × 3 = 210,
30/70 = 30 × 3/70 × 3 = 90/210 - Subtract the two like fractions:
30/210 - 90/210 = 30 - 90/210 = -60/210 - After reducing the fraction, the answer is -2/7
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 6/21-30/70 3/21-60/70 3/42-30/70 9/21-30/70 3/21-90/70 3/63-30/70 15/21-30/70