Subtract 15/30 from 21/42
21/42 - 15/30 is 0/1.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 42 and 30 is 210
Next, find the equivalent fraction of both fractional numbers with denominator 210 - For the 1st fraction, since 42 × 5 = 210,
21/42 = 21 × 5/42 × 5 = 105/210 - Likewise, for the 2nd fraction, since 30 × 7 = 210,
15/30 = 15 × 7/30 × 7 = 105/210 - Subtract the two like fractions:
105/210 - 105/210 = 105 - 105/210 = 0/210 - The answer is 0
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 21/84-15/30 21/42-15/60 63/42-15/30 21/42-45/30 21/42-15/90 21/42-75/30