Subtract 42/84 from 21/27
21/27 - 42/84 is 5/18.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 27 and 84 is 756
Next, find the equivalent fraction of both fractional numbers with denominator 756 - For the 1st fraction, since 27 × 28 = 756,
21/27 = 21 × 28/27 × 28 = 588/756 - Likewise, for the 2nd fraction, since 84 × 9 = 756,
42/84 = 42 × 9/84 × 9 = 378/756 - Subtract the two like fractions:
588/756 - 378/756 = 588 - 378/756 = 210/756 - After reducing the fraction, the answer is 5/18
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 42/27-42/84 21/54-42/84 63/27-42/84 21/81-42/84