Subtract 1/40 from 5/42
5/42 - 1/40 is 79/840.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 42 and 40 is 840
Next, find the equivalent fraction of both fractional numbers with denominator 840 - For the 1st fraction, since 42 × 20 = 840,
5/42 = 5 × 20/42 × 20 = 100/840 - Likewise, for the 2nd fraction, since 40 × 21 = 840,
1/40 = 1 × 21/40 × 21 = 21/840 - Subtract the two like fractions:
100/840 - 21/840 = 100 - 21/840 = 79/840
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 10/42-1/40 5/42-2/40 5/84-1/40 5/42-1/80 15/42-1/40 5/42-3/40 25/42-1/40 5/42-5/40 35/42-1/40 5/42-7/40