Subtract 90/42 from 20/40
1st number: 20/40, 2nd number: 2 6/42
20/40 - 90/42 is -23/14.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 40 and 42 is 840
Next, find the equivalent fraction of both fractional numbers with denominator 840 - For the 1st fraction, since 40 × 21 = 840,
20/40 = 20 × 21/40 × 21 = 420/840 - Likewise, for the 2nd fraction, since 42 × 20 = 840,
90/42 = 90 × 20/42 × 20 = 1800/840 - Subtract the two like fractions:
420/840 - 1800/840 = 420 - 1800/840 = -1380/840 - After reducing the fraction, the answer is -23/14
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 20/80-90/42 20/40-90/84 60/40-90/42