Friday, August 24, 2012

Multiplying two 2-digit numbers (difference of 8)


Follow the following Steps:

  1. Choose a 2-digit number.
  2. Select a number either 8 smaller or 8 larger.
  3. Find the middle number of the two (the average).
  4. Square this middle number (multiply it by itself).
  5. Subtract 16 from this square.

   Example-1:

  1. If the first number is 34, choose 26 as the second number (8 smaller).
  2. The middle number (the average) is 30.
  3. Square this middle number: 30 × 30 = 900.
  4. Subtract 16 from this square: 900 - 16 = 884.
  5. So 34 × 26 = 884.
   

Example-2:

  1. If the first number is 64, choose 72 as the second number (8 larger).
  2. The middle number (the average) is 68.
  3. Square this middle number: 68 × 68 = 4624.
  4. Subtract 16 from this square: 4624 - 16 = 4608.
  5. So 64 × 72 = 4608.

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