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Multiplying A 2-digit Number By 43

Multiplying A 2-digit Number By 43

Multiplying a 2-digit number by 43

  1. Select a 2-digit number.
  2. Multiply the number by four.
  3. Add one zero.
  4. To this add three times the original number.
   Example:
  1. The 2-digit number chosen to multiply by 43 is 21.
  2. Multiply by 4: 4 × 21 = 84.
  3. Add one zero: 840.
  4. To this add three times the original number: 840 + 3(21) = 840 + 63 = 900 + 3 = 903.
  5. So 43 × 21 is 903.

   See the pattern?

  1. The 2-digit number chosen to multiply by 43 is 52.
  2. Multiply by 4: 4 × 52 = 200 + 8 = 208.
  3. Add one zero: 2080.
  4. To this add three times the original number: 2080 + 3(52) = 2080 + 150 + 6 = 2180 + 50 + 6 = 2230 + 6 = 2236.
  5. So 43 × 52 is 2236.

 

Remember to add and multiply left to right in manageable increments, and you will be able to give these products using mental math.




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26 Sep, 2021, 02:20:40 AM