Subtract 9/70 from 21/72
21/72 - 9/70 is 137/840.
Steps for subtracting fractions
- Find the least common denominator or LCM of the two denominators:
LCM of 72 and 70 is 2520
Next, find the equivalent fraction of both fractional numbers with denominator 2520 - For the 1st fraction, since 72 × 35 = 2520,
21/72 = 21 × 35/72 × 35 = 735/2520 - Likewise, for the 2nd fraction, since 70 × 36 = 2520,
9/70 = 9 × 36/70 × 36 = 324/2520 - Subtract the two like fractions:
735/2520 - 324/2520 = 735 - 324/2520 = 411/2520 - After reducing the fraction, the answer is 137/840
MathStep (Works offline)
Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad
Related: 42/72-9/70 21/72-18/70 63/72-9/70 21/72-27/70 21/72-45/70 21/72-63/70