Subtract 4/15 from 30/21
1st number: 1 9/21, 2nd number: 4/15
30/21 - 4/15 is 122/105.
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,
30/21 = 30 × 5/21 × 5 = 150/105 - Likewise, for the 2nd fraction, since 15 × 7 = 105,
4/15 = 4 × 7/15 × 7 = 28/105 - Subtract the two like fractions:
150/105 - 28/105 = 150 - 28/105 = 122/105 - In mixed form: 117/105
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 60/21-4/15 30/21-8/15 30/42-4/15 30/21-4/30 90/21-4/15 30/21-12/15 30/63-4/15 30/21-4/45 30/21-20/15 30/21-4/75 30/21-28/15