Subtract 21/3 from 18/42
1st number: 18/42, 2nd number: 7 0/3
18/42 - 21/3 is -46/7.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 42 and 3 is 42
Next, find the equivalent fraction of both fractional numbers with denominator 42 - For the 1st fraction, since 42 × 1 = 42,
18/42 = 18 × 1/42 × 1 = 18/42 - Likewise, for the 2nd fraction, since 3 × 14 = 42,
21/3 = 21 × 14/3 × 14 = 294/42 - Subtract the two like fractions:
18/42 - 294/42 = 18 - 294/42 = -276/42 - After reducing the fraction, the answer is -46/7
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 36/42-21/3 18/42-42/3 18/84-21/3 18/42-21/6 54/42-21/3 18/42-63/3 18/42-21/9 90/42-21/3 18/42-21/15