Subtract 28/40 from 3/7
3/7 - 28/40 is -19/70.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 7 and 40 is 280
Next, find the equivalent fraction of both fractional numbers with denominator 280 - For the 1st fraction, since 7 × 40 = 280,
3/7 = 3 × 40/7 × 40 = 120/280 - Likewise, for the 2nd fraction, since 40 × 7 = 280,
28/40 = 28 × 7/40 × 7 = 196/280 - Subtract the two like fractions:
120/280 - 196/280 = 120 - 196/280 = -76/280 - After reducing the fraction, the answer is -19/70
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 6/7-28/40 3/7-56/40 3/14-28/40 3/7-28/80 9/7-28/40 3/7-84/40 3/21-28/40 15/7-28/40 3/35-28/40 21/7-28/40 3/49-28/40