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Subtract 21/10 from 4/81

1st number: 4/81, 2nd number: 2 1/10

4/81 - 21/10 is -1661/810.

Steps for subtracting fractions

  1. Find the least common denominator or LCM of the two denominators:
    LCM of 81 and 10 is 810

    Next, find the equivalent fraction of both fractional numbers with denominator 810
  2. For the 1st fraction, since 81 × 10 = 810,
    4/81 = 4 × 10/81 × 10 = 40/810
  3. Likewise, for the 2nd fraction, since 10 × 81 = 810,
    21/10 = 21 × 81/10 × 81 = 1701/810
  4. Subtract the two like fractions:
    40/810 - 1701/810 = 40 - 1701/810 = -1661/810

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