Subtract 42/5 from 28/21
1st number: 1 7/21, 2nd number: 8 2/5
28/21 - 42/5 is -106/15.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 21 and 5 is 105
Next, find the equivalent fraction of both fractional numbers with denominator 105 - For the 1st fraction, since 21 × 5 = 105,
28/21 = 28 × 5/21 × 5 = 140/105 - Likewise, for the 2nd fraction, since 5 × 21 = 105,
42/5 = 42 × 21/5 × 21 = 882/105 - Subtract the two like fractions:
140/105 - 882/105 = 140 - 882/105 = -742/105 - After reducing the fraction, the answer is -106/15
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 56/21-42/5 28/21-84/5 28/42-42/5 28/21-42/10 84/21-42/5 28/63-42/5 28/21-42/15 28/21-42/25 28/21-42/35