Subtract 20/8 from 18/84
1st number: 18/84, 2nd number: 2 4/8
18/84 - 20/8 is -16/7.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 84 and 8 is 168
Next, find the equivalent fraction of both fractional numbers with denominator 168 - For the 1st fraction, since 84 × 2 = 168,
18/84 = 18 × 2/84 × 2 = 36/168 - Likewise, for the 2nd fraction, since 8 × 21 = 168,
20/8 = 20 × 21/8 × 21 = 420/168 - Subtract the two like fractions:
36/168 - 420/168 = 36 - 420/168 = -384/168 - After reducing the fraction, the answer is -16/7
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 36/84-20/8 18/84-40/8 18/84-20/16 54/84-20/8 18/84-60/8 18/84-20/24 90/84-20/8 18/84-20/40 18/84-20/56