Answers

Solutions by everydaycalculation.com

Everydaycalculation.com » Answers » Subtract fractions

Subtract 72/70 from 21/90

1st number: 21/90, 2nd number: 1 2/70

21/90 - 72/70 is -167/210.

Steps for subtracting fractions

  1. Find the least common denominator or LCM of the two denominators:
    LCM of 90 and 70 is 630
  2. For the 1st fraction, since 90 × 7 = 630,
    21/90 = 21 × 7/90 × 7 = 147/630
  3. Likewise, for the 2nd fraction, since 70 × 9 = 630,
    72/70 = 72 × 9/70 × 9 = 648/630
  4. Subtract the two fractions:
    147/630 - 648/630 = 147 - 648/630 = -501/630
  5. After reducing the fraction, the answer is -167/210

MathStep (Works offline)

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

Related:

© everydaycalculation.com