Subtract 30/15 from 8/21
1st number: 8/21, 2nd number: 2 0/15
8/21 - 30/15 is -34/21.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 21 and 15 is 105
Next, find the equivalent fraction of both fractional numbers with denominator 105 - For the 1st fraction, since 21 × 5 = 105,
8/21 = 8 × 5/21 × 5 = 40/105 - Likewise, for the 2nd fraction, since 15 × 7 = 105,
30/15 = 30 × 7/15 × 7 = 210/105 - Subtract the two like fractions:
40/105 - 210/105 = 40 - 210/105 = -170/105 - After reducing the fraction, the answer is -34/21
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 16/21-30/15 8/21-60/15 8/42-30/15 24/21-30/15 8/21-90/15 8/63-30/15 8/21-30/45 40/21-30/15 8/21-30/75 56/21-30/15