Calculating 46 x 77 in 5 seconds.



Conditions:
  1. The multiplier is a two digits number, and a multiple of 11, such as 22, 33, 44, 55 and so on.
  2. The multiplicand is also a two digits number, where the two digits add up to 10. In this case, 4 + 6 = 10.

Example 1
  1. Take the tens digit of the multiplicand, increase it by one, and then multiply it by any one of the digit of the multiplier. In this case it’s 7. So, we get 35. This will be the last 2 digits of the answer.
  2. Multiply the first digits of the two numbers. In this case, we get 42. This will be the first 2 digits of the answer.


Example 2
82 x 44 = ?

(8 + 1) x 4 = 36
2 x 4 = 8

Therefore,
82 x 44 = = 3608

Example 3
37 x 22 = ?

(3 + 1) x 2 = 8
7 x 2 = 14

Therefore,
37 x 22 = 814

0 comments:

Post a Comment