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Add 15/40 and 20/42

15/40 + 20/42 is 143/168.

Steps for adding fractions

  1. Find the least common denominator or LCM of the two denominators:
    LCM of 40 and 42 is 840

    Next, find the equivalent fraction of both fractional numbers with denominator 840
  2. For the 1st fraction, since 40 × 21 = 840,
    15/40 = 15 × 21/40 × 21 = 315/840
  3. Likewise, for the 2nd fraction, since 42 × 20 = 840,
    20/42 = 20 × 20/42 × 20 = 400/840
  4. Add the two like fractions:
    315/840 + 400/840 = 315 + 400/840 = 715/840
  5. 715/840 simplified gives 143/168
  6. So, 15/40 + 20/42 = 143/168

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