Subtract 18/21 from 2/5
2/5 - 18/21 is -16/35.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 5 and 21 is 105
Next, find the equivalent fraction of both fractional numbers with denominator 105 - For the 1st fraction, since 5 × 21 = 105,
2/5 = 2 × 21/5 × 21 = 42/105 - Likewise, for the 2nd fraction, since 21 × 5 = 105,
18/21 = 18 × 5/21 × 5 = 90/105 - Subtract the two like fractions:
42/105 - 90/105 = 42 - 90/105 = -48/105 - After reducing the fraction, the answer is -16/35
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 4/5-18/21 2/5-36/21 2/10-18/21 2/5-18/42 6/5-18/21 2/5-54/21 2/15-18/21 2/5-18/63 10/5-18/21 2/5-90/21 2/25-18/21 14/5-18/21 2/35-18/21