Subtract 18/10 from 15/21
1st number: 15/21, 2nd number: 1 8/10
15/21 - 18/10 is -38/35.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 21 and 10 is 210
Next, find the equivalent fraction of both fractional numbers with denominator 210 - For the 1st fraction, since 21 × 10 = 210,
15/21 = 15 × 10/21 × 10 = 150/210 - Likewise, for the 2nd fraction, since 10 × 21 = 210,
18/10 = 18 × 21/10 × 21 = 378/210 - Subtract the two like fractions:
150/210 - 378/210 = 150 - 378/210 = -228/210 - After reducing the fraction, the answer is -38/35
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 30/21-18/10 15/21-36/10 15/42-18/10 15/21-18/20 45/21-18/10 15/21-54/10 15/63-18/10 15/21-18/30 75/21-18/10 15/21-90/10 15/21-18/50 15/21-18/70