Subtract 18/40 from 30/80
30/80 - 18/40 is -3/40.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 80 and 40 is 80
Next, find the equivalent fraction of both fractional numbers with denominator 80 - For the 1st fraction, since 80 × 1 = 80,
30/80 = 30 × 1/80 × 1 = 30/80 - Likewise, for the 2nd fraction, since 40 × 2 = 80,
18/40 = 18 × 2/40 × 2 = 36/80 - Subtract the two like fractions:
30/80 - 36/80 = 30 - 36/80 = -6/80 - After reducing the fraction, the answer is -3/40
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 60/80-18/40 30/80-36/40 30/80-18/80 90/80-18/40 30/80-54/40 30/80-90/40