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Subtract 18/9 from 72/21

1st number: 3 9/21, 2nd number: 2 0/9

72/21 - 18/9 is 10/7.

Steps for subtracting fractions

  1. Find the least common denominator or LCM of the two denominators:
    LCM of 21 and 9 is 63
  2. For the 1st fraction, since 21 × 3 = 63,
    72/21 = 72 × 3/21 × 3 = 216/63
  3. Likewise, for the 2nd fraction, since 9 × 7 = 63,
    18/9 = 18 × 7/9 × 7 = 126/63
  4. Subtract the two fractions:
    216/63 - 126/63 = 216 - 126/63 = 90/63
  5. After reducing the fraction, the answer is 10/7
  6. In mixed form: 13/7

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