Subtract 42/56 from 20/45
20/45 - 42/56 is -11/36.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 45 and 56 is 2520
Next, find the equivalent fraction of both fractional numbers with denominator 2520 - For the 1st fraction, since 45 × 56 = 2520,
20/45 = 20 × 56/45 × 56 = 1120/2520 - Likewise, for the 2nd fraction, since 56 × 45 = 2520,
42/56 = 42 × 45/56 × 45 = 1890/2520 - Subtract the two like fractions:
1120/2520 - 1890/2520 = 1120 - 1890/2520 = -770/2520 - After reducing the fraction, the answer is -11/36
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 40/45-42/56 20/45-84/56 20/90-42/56 60/45-42/56