Subtract 3/21 from 8/42
8/42 - 3/21 is 1/21.
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,
8/42 = 8 × 1/42 × 1 = 8/42 - Likewise, for the 2nd fraction, since 21 × 2 = 42,
3/21 = 3 × 2/21 × 2 = 6/42 - Subtract the two like fractions:
8/42 - 6/42 = 8 - 6/42 = 2/42 - After reducing the fraction, the answer is 1/21
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 16/42-3/21 8/42-6/21 8/84-3/21 8/42-3/42 24/42-3/21 8/42-9/21 8/42-3/63 40/42-3/21 8/42-15/21 56/42-3/21