Subtract 10/21 from 10/42
10/42 - 10/21 is -5/21.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 42 and 21 is 42
Next, find the equivalent fraction of both fractional numbers with denominator 42 - For the 1st fraction, since 42 × 1 = 42,
10/42 = 10 × 1/42 × 1 = 10/42 - Likewise, for the 2nd fraction, since 21 × 2 = 42,
10/21 = 10 × 2/21 × 2 = 20/42 - Subtract the two like fractions:
10/42 - 20/42 = 10 - 20/42 = -10/42 - After reducing the fraction, the answer is -5/21
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 20/42-10/21 10/42-20/21 10/84-10/21 10/42-10/42 30/42-10/21 10/42-30/21 10/42-10/63 50/42-10/21 10/42-50/21 70/42-10/21 10/42-70/21