Subtract 18/21 from 20/15
1st number: 1 5/15, 2nd number: 18/21
20/15 - 18/21 is 10/21.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 15 and 21 is 105
Next, find the equivalent fraction of both fractional numbers with denominator 105 - For the 1st fraction, since 15 × 7 = 105,
20/15 = 20 × 7/15 × 7 = 140/105 - Likewise, for the 2nd fraction, since 21 × 5 = 105,
18/21 = 18 × 5/21 × 5 = 90/105 - Subtract the two like fractions:
140/105 - 90/105 = 140 - 90/105 = 50/105 - 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: 40/15-18/21 20/15-36/21 20/30-18/21 20/15-18/42 60/15-18/21 20/15-54/21 20/45-18/21 20/15-18/63 20/15-90/21 20/75-18/21