Subtract 15/20 from 28/81
28/81 - 15/20 is -131/324.
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,
15/20 = 15 × 81/20 × 81 = 1215/1620 - Subtract the two like fractions:
560/1620 - 1215/1620 = 560 - 1215/1620 = -655/1620 - After reducing the fraction, the answer is -131/324
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 56/81-15/20 28/81-30/20 28/81-15/40 84/81-15/20 28/81-45/20 28/81-15/60 28/81-75/20