Subtract 1/20 from 28/81
28/81 - 1/20 is 479/1620.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 81 and 20 is 1620
Next, find the equivalent fraction of both fractional numbers with denominator 1620 - For the 1st fraction, since 81 × 20 = 1620,
28/81 = 28 × 20/81 × 20 = 560/1620 - Likewise, for the 2nd fraction, since 20 × 81 = 1620,
1/20 = 1 × 81/20 × 81 = 81/1620 - Subtract the two like fractions:
560/1620 - 81/1620 = 560 - 81/1620 = 479/1620
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 56/81-1/20 28/81-2/20 28/81-1/40 84/81-1/20 28/81-3/20 28/81-1/60 28/81-5/20 28/81-7/20