Subtract 1/40 from 12/21
12/21 - 1/40 is 153/280.
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,
12/21 = 12 × 40/21 × 40 = 480/840 - Likewise, for the 2nd fraction, since 40 × 21 = 840,
1/40 = 1 × 21/40 × 21 = 21/840 - Subtract the two like fractions:
480/840 - 21/840 = 480 - 21/840 = 459/840 - After reducing the fraction, the answer is 153/280
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 24/21-1/40 12/21-2/40 12/42-1/40 12/21-1/80 36/21-1/40 12/21-3/40 12/63-1/40 60/21-1/40 12/21-5/40 84/21-1/40 12/21-7/40