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Multiplying A 2-digit Number By 792

Multiplying A 2-digit Number By 792

Multiplying a 2-digit number by 792

  1. Select a 2-digit number.
  2. Multiply it by 8.
  3. Add two zeros.
  4. Subtract the original number from the result.
   Example:
  1. The 2-digit number chosen to multiply by 792 is 22.
  2. Multiply by 8: 8 × 22 = 176
    (Think: 8 × 20 + 8 × 22 = 176)
  3. Add two zeros: 17600
  4. Subtract 17600 - 176 = 17424
    (Think: 17600 - 100 - 70 - 6 = 17500 - 70 - 6
    = 17430 - 6 = 17424)
  5. So 22 × 792 = 17,424.

   See the pattern?

  1. The 2-digit number chosen to multiply by 792 is 91.
  2. Multiply by 8: 8 × 91 = 728
    (Think: 8 × 90 + 8 × 1 = 720 + 8 = 728)
  3. Add two zeros: 72800
  4. Subtract 72800 - 728 = 72072
    (Think: 72800 - 700 - 20 - 8 = 72100 - 20 - 8
    = 72080 - 8 = 72072)
  5. So 91 × 792 = 72,072.

Practice the left-to-right subtraction. Think each step to yourself as a cue for the next.





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31 Mar, 2020, 22:42:27 PM