Subtract 18/12 from 20/90
1st number: 20/90, 2nd number: 1 6/12
20/90 - 18/12 is -23/18.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 90 and 12 is 180
Next, find the equivalent fraction of both fractional numbers with denominator 180 - For the 1st fraction, since 90 × 2 = 180,
20/90 = 20 × 2/90 × 2 = 40/180 - Likewise, for the 2nd fraction, since 12 × 15 = 180,
18/12 = 18 × 15/12 × 15 = 270/180 - Subtract the two like fractions:
40/180 - 270/180 = 40 - 270/180 = -230/180 - After reducing the fraction, the answer is -23/18
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 40/90-18/12 20/90-36/12 20/90-18/24 60/90-18/12 20/90-54/12 20/90-18/36 20/90-90/12 20/90-18/60 20/90-18/84