Subtract 40/42 from 3/10
3/10 - 40/42 is -137/210.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 10 and 42 is 210
Next, find the equivalent fraction of both fractional numbers with denominator 210 - For the 1st fraction, since 10 × 21 = 210,
3/10 = 3 × 21/10 × 21 = 63/210 - Likewise, for the 2nd fraction, since 42 × 5 = 210,
40/42 = 40 × 5/42 × 5 = 200/210 - Subtract the two like fractions:
63/210 - 200/210 = 63 - 200/210 = -137/210
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 6/10-40/42 3/10-80/42 3/20-40/42 3/10-40/84 9/10-40/42 3/30-40/42 15/10-40/42 3/50-40/42 21/10-40/42 3/70-40/42