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Subtract 20/21 from 15/8

1st number: 1 7/8, 2nd number: 20/21

15/8 - 20/21 is 155/168.

Steps for subtracting fractions

  1. Find the least common denominator or LCM of the two denominators:
    LCM of 8 and 21 is 168
  2. For the 1st fraction, since 8 × 21 = 168,
    15/8 = 15 × 21/8 × 21 = 315/168
  3. Likewise, for the 2nd fraction, since 21 × 8 = 168,
    20/21 = 20 × 8/21 × 8 = 160/168
  4. Subtract the two fractions:
    315/168 - 160/168 = 315 - 160/168 = 155/168

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