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Subtract 40/21 from 20/45

1st number: 20/45, 2nd number: 1 19/21

20/45 - 40/21 is -92/63.

Steps for subtracting fractions

  1. Find the least common denominator or LCM of the two denominators:
    LCM of 45 and 21 is 315

    Next, find the equivalent fraction of both fractional numbers with denominator 315
  2. For the 1st fraction, since 45 × 7 = 315,
    20/45 = 20 × 7/45 × 7 = 140/315
  3. Likewise, for the 2nd fraction, since 21 × 15 = 315,
    40/21 = 40 × 15/21 × 15 = 600/315
  4. Subtract the two like fractions:
    140/315 - 600/315 = 140 - 600/315 = -460/315
  5. After reducing the fraction, the answer is -92/63

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