Subtract 36/18 from 28/21
1st number: 1 7/21, 2nd number: 2 0/18
28/21 - 36/18 is -2/3.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 21 and 18 is 126
Next, find the equivalent fraction of both fractional numbers with denominator 126 - For the 1st fraction, since 21 × 6 = 126,
28/21 = 28 × 6/21 × 6 = 168/126 - Likewise, for the 2nd fraction, since 18 × 7 = 126,
36/18 = 36 × 7/18 × 7 = 252/126 - Subtract the two like fractions:
168/126 - 252/126 = 168 - 252/126 = -84/126 - After reducing the fraction, the answer is -2/3
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 56/21-36/18 28/21-72/18 28/42-36/18 84/21-36/18 28/63-36/18 28/21-36/54 28/21-36/90