Subtract 15/27 from 42/84
42/84 - 15/27 is -1/18.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 84 and 27 is 756
Next, find the equivalent fraction of both fractional numbers with denominator 756 - For the 1st fraction, since 84 × 9 = 756,
42/84 = 42 × 9/84 × 9 = 378/756 - Likewise, for the 2nd fraction, since 27 × 28 = 756,
15/27 = 15 × 28/27 × 28 = 420/756 - Subtract the two like fractions:
378/756 - 420/756 = 378 - 420/756 = -42/756 - After reducing the fraction, the answer is -1/18
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 42/84-30/27 42/84-15/54 42/84-45/27 42/84-15/81 42/84-75/27