Subtract 12/8 from 20/42
1st number: 20/42, 2nd number: 1 4/8
20/42 - 12/8 is -43/42.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 42 and 8 is 168
Next, find the equivalent fraction of both fractional numbers with denominator 168 - For the 1st fraction, since 42 × 4 = 168,
20/42 = 20 × 4/42 × 4 = 80/168 - Likewise, for the 2nd fraction, since 8 × 21 = 168,
12/8 = 12 × 21/8 × 21 = 252/168 - Subtract the two like fractions:
80/168 - 252/168 = 80 - 252/168 = -172/168 - After reducing the fraction, the answer is -43/42
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 40/42-12/8 20/42-24/8 20/84-12/8 20/42-12/16 60/42-12/8 20/42-36/8 20/42-12/24 20/42-60/8 20/42-12/40 20/42-84/8 20/42-12/56