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Add 18/21 and 12/40

18/21 + 12/40 is 81/70.

Steps for adding fractions

  1. Find the least common denominator or LCM of the two denominators:
    LCM of 21 and 40 is 840

    Next, find the equivalent fraction of both fractional numbers with denominator 840
  2. For the 1st fraction, since 21 × 40 = 840,
    18/21 = 18 × 40/21 × 40 = 720/840
  3. Likewise, for the 2nd fraction, since 40 × 21 = 840,
    12/40 = 12 × 21/40 × 21 = 252/840
  4. Add the two like fractions:
    720/840 + 252/840 = 720 + 252/840 = 972/840
  5. 972/840 simplified gives 81/70
  6. So, 18/21 + 12/40 = 81/70
    In mixed form: 111/70

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