Subtract 45/21 from 18/28
1st number: 18/28, 2nd number: 2 3/21
18/28 - 45/21 is -3/2.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 28 and 21 is 84
Next, find the equivalent fraction of both fractional numbers with denominator 84 - For the 1st fraction, since 28 × 3 = 84,
18/28 = 18 × 3/28 × 3 = 54/84 - Likewise, for the 2nd fraction, since 21 × 4 = 84,
45/21 = 45 × 4/21 × 4 = 180/84 - Subtract the two like fractions:
54/84 - 180/84 = 54 - 180/84 = -126/84 - After reducing the fraction, the answer is -3/2
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 36/28-45/21 18/28-90/21 18/56-45/21 18/28-45/42 54/28-45/21 18/84-45/21 18/28-45/63 90/28-45/21