Subtract 30/40 from 6/21
6/21 - 30/40 is -13/28.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 21 and 40 is 840
Next, find the equivalent fraction of both fractional numbers with denominator 840 - For the 1st fraction, since 21 × 40 = 840,
6/21 = 6 × 40/21 × 40 = 240/840 - Likewise, for the 2nd fraction, since 40 × 21 = 840,
30/40 = 30 × 21/40 × 21 = 630/840 - Subtract the two like fractions:
240/840 - 630/840 = 240 - 630/840 = -390/840 - After reducing the fraction, the answer is -13/28
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 12/21-30/40 6/21-60/40 6/42-30/40 6/21-30/80 18/21-30/40 6/21-90/40 6/63-30/40 30/21-30/40 42/21-30/40