Subtract 1/54 from 21/42
21/42 - 1/54 is 13/27.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 42 and 54 is 378
Next, find the equivalent fraction of both fractional numbers with denominator 378 - For the 1st fraction, since 42 × 9 = 378,
21/42 = 21 × 9/42 × 9 = 189/378 - Likewise, for the 2nd fraction, since 54 × 7 = 378,
1/54 = 1 × 7/54 × 7 = 7/378 - Subtract the two like fractions:
189/378 - 7/378 = 189 - 7/378 = 182/378 - After reducing the fraction, the answer is 13/27
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 21/42-2/54 21/84-1/54 63/42-1/54 21/42-3/54 21/42-5/54 21/42-7/54