Subtract 70/4 from 42/21
1st number: 2 0/21, 2nd number: 17 2/4
42/21 - 70/4 is -31/2.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 21 and 4 is 84
Next, find the equivalent fraction of both fractional numbers with denominator 84 - For the 1st fraction, since 21 × 4 = 84,
42/21 = 42 × 4/21 × 4 = 168/84 - Likewise, for the 2nd fraction, since 4 × 21 = 84,
70/4 = 70 × 21/4 × 21 = 1470/84 - Subtract the two like fractions:
168/84 - 1470/84 = 168 - 1470/84 = -1302/84 - After reducing the fraction, the answer is -31/2
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 84/21-70/4 42/21-70/8 42/63-70/4 42/21-70/12 42/21-70/20 42/21-70/28