Subtract 42/21 from 1/20
1st number: 1/20, 2nd number: 2 0/21
1/20 - 42/21 is -39/20.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 20 and 21 is 420
Next, find the equivalent fraction of both fractional numbers with denominator 420 - For the 1st fraction, since 20 × 21 = 420,
1/20 = 1 × 21/20 × 21 = 21/420 - Likewise, for the 2nd fraction, since 21 × 20 = 420,
42/21 = 42 × 20/21 × 20 = 840/420 - Subtract the two like fractions:
21/420 - 840/420 = 21 - 840/420 = -819/420 - After reducing the fraction, the answer is -39/20
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 2/20-42/21 1/20-84/21 1/40-42/21 3/20-42/21 1/60-42/21 1/20-42/63 5/20-42/21 7/20-42/21