Subtract 21/18 from 42/48
1st number: 42/48, 2nd number: 1 3/18
42/48 - 21/18 is -7/24.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 48 and 18 is 144
Next, find the equivalent fraction of both fractional numbers with denominator 144 - For the 1st fraction, since 48 × 3 = 144,
42/48 = 42 × 3/48 × 3 = 126/144 - Likewise, for the 2nd fraction, since 18 × 8 = 144,
21/18 = 21 × 8/18 × 8 = 168/144 - Subtract the two like fractions:
126/144 - 168/144 = 126 - 168/144 = -42/144 - After reducing the fraction, the answer is -7/24
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 84/48-21/18 42/48-42/18 42/96-21/18 42/48-21/36 42/48-63/18 42/48-21/54 42/48-21/90