How do those seemingly mental math geniuses do it? Are their brains really programmed differently, allowing them to do what seems to be mental magic? What gives here? Maybe they have integrated circuits instead of dendrites?
The truth is, they more than likely know a number (excuse the bad pun) of math tricks that allow them to quickly find answers to math certain operations. There are many short cuts that can be employed for math problems involving addition, subtraction, multiplication, and division. If you spend some time rehearsing these methods, then you too can perform these seemingly miraculous feats.
For instance, suppose you wanted to multiple 43 x 11. Well, you may be able to solve this problem in your head already if you realize that you can first multiply 43 by 10, and then adding 43 to the result. Sure enough, the answer is 473. This works relatively quickly, but there is another method that you can use to get the answer more quickly!
This is a special case for multiplying two-digit numbers by 11. Indeed, the method can be used more generally on larger digit-numbers, but let’s look at how to employ this method with two-digit numbers:
First, take the digits in the number you are multiplying by 11, and add them. In our case (43), it is 4 + 3 = 7. Now take the result, and place in between the two-digit number. In our case, take the “7” and place it between the “4” and “3”. Did you see the result? Right! it is the answer 473!
Pretty neat, huh? Keep in mind that other problems may involve carrying-over numbers, but with a little practice, this will become almost natural.
This was a special case for numbers multiplied by 11, but there are many other methods you can use to calculate more complex problems quickly in your head.
Find out how to perform mental math faster than a calculator!