Subtract 18/81 from 3/20
3/20 - 18/81 is -13/180.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 20 and 81 is 1620
Next, find the equivalent fraction of both fractional numbers with denominator 1620 - For the 1st fraction, since 20 × 81 = 1620,
3/20 = 3 × 81/20 × 81 = 243/1620 - Likewise, for the 2nd fraction, since 81 × 20 = 1620,
18/81 = 18 × 20/81 × 20 = 360/1620 - Subtract the two like fractions:
243/1620 - 360/1620 = 243 - 360/1620 = -117/1620 - After reducing the fraction, the answer is -13/180
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 6/20-18/81 3/20-36/81 3/40-18/81 9/20-18/81 3/20-54/81 3/60-18/81 15/20-18/81 3/20-90/81 21/20-18/81