Subtract 18/21 from 1/4
1/4 - 18/21 is -17/28.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 4 and 21 is 84
Next, find the equivalent fraction of both fractional numbers with denominator 84 - For the 1st fraction, since 4 × 21 = 84,
1/4 = 1 × 21/4 × 21 = 21/84 - Likewise, for the 2nd fraction, since 21 × 4 = 84,
18/21 = 18 × 4/21 × 4 = 72/84 - Subtract the two like fractions:
21/84 - 72/84 = 21 - 72/84 = -51/84 - After reducing the fraction, the answer is -17/28
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 2/4-18/21 1/4-36/21 1/8-18/21 1/4-18/42 3/4-18/21 1/4-54/21 1/12-18/21 1/4-18/63 5/4-18/21 1/4-90/21 1/20-18/21 7/4-18/21 1/28-18/21