Subtract 5/42 from 20/40
20/40 - 5/42 is 8/21.
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,
5/42 = 5 × 20/42 × 20 = 100/840 - Subtract the two like fractions:
420/840 - 100/840 = 420 - 100/840 = 320/840 - After reducing the fraction, the answer is 8/21
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 20/40-10/42 20/80-5/42 20/40-5/84 60/40-5/42 20/40-15/42 20/40-25/42 20/40-35/42