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Subtract 72/10 from 21/90

1st number: 21/90, 2nd number: 7 2/10

21/90 - 72/10 is -209/30.

Steps for subtracting fractions

  1. Find the least common denominator or LCM of the two denominators:
    LCM of 90 and 10 is 90
  2. For the 1st fraction, since 90 × 1 = 90,
    21/90 = 21 × 1/90 × 1 = 21/90
  3. Likewise, for the 2nd fraction, since 10 × 9 = 90,
    72/10 = 72 × 9/10 × 9 = 648/90
  4. Subtract the two fractions:
    21/90 - 648/90 = 21 - 648/90 = -627/90
  5. After reducing the fraction, the answer is -209/30

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