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Add 21/40 and 12/20

21/40 + 12/20 is 9/8.

Steps for adding fractions

  1. Find the least common denominator or LCM of the two denominators:
    LCM of 40 and 20 is 40

    Next, find the equivalent fraction of both fractional numbers with denominator 40
  2. For the 1st fraction, since 40 × 1 = 40,
    21/40 = 21 × 1/40 × 1 = 21/40
  3. Likewise, for the 2nd fraction, since 20 × 2 = 40,
    12/20 = 12 × 2/20 × 2 = 24/40
  4. Add the two like fractions:
    21/40 + 24/40 = 21 + 24/40 = 45/40
  5. 45/40 simplified gives 9/8
  6. So, 21/40 + 12/20 = 9/8
    In mixed form: 11/8

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