Subtract 30/21 from 18/15
1st number: 1 3/15, 2nd number: 1 9/21
18/15 - 30/21 is -8/35.
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,
18/15 = 18 × 7/15 × 7 = 126/105 - Likewise, for the 2nd fraction, since 21 × 5 = 105,
30/21 = 30 × 5/21 × 5 = 150/105 - Subtract the two like fractions:
126/105 - 150/105 = 126 - 150/105 = -24/105 - After reducing the fraction, the answer is -8/35
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 36/15-30/21 18/15-60/21 18/30-30/21 18/15-30/42 54/15-30/21 18/15-90/21 18/45-30/21 18/15-30/63 90/15-30/21 18/75-30/21