Answers

Solutions by everydaycalculation.com

Everydaycalculation.com » Answers » Subtract fractions

Subtract 20/21 from 15/40

15/40 - 20/21 is -97/168.

Steps for subtracting fractions

  1. Find the least common denominator or LCM of the two denominators:
    LCM of 40 and 21 is 840
  2. For the 1st fraction, since 40 × 21 = 840,
    15/40 = 15 × 21/40 × 21 = 315/840
  3. Likewise, for the 2nd fraction, since 21 × 40 = 840,
    20/21 = 20 × 40/21 × 40 = 800/840
  4. Subtract the two fractions:
    315/840 - 800/840 = 315 - 800/840 = -485/840
  5. After reducing the fraction, the answer is -97/168

MathStep (Works offline)

Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad

Related:

© everydaycalculation.com