Multiply

 

Mutliply any two numbers easily in your head metally. ( THIS IS NOT JUST party trick, it will let you do many handy calculations ).

We' ll start with an example:

23 x 35 

So first we will multiply the last digit of both numbers, in this case the two numbers are three and five which mutiply to fifteen. so we take the number 5 as last digit of final answer and hold the 1 as remainder  and carry it to left.

Now, we multiply the last digit of the first number with the first digit of the last number and vice versa and plus them,in this case, it will be 2 x 5 = 10 and 3 x 3 = 9 which add up to 19. Since we have the remainder of the previous calculation of 1 we add it and it becomes 20 and the we write down 0 as second last digit of final answer. We take two as carry. Now finally, we multiply first digit of both which in this case is 2 x 3 = 6 so with carry of 2 added, it becomes 8.

so final answer is 805.

All of this might look a bit tedious but if you think about it if you directly (with normal way) try to do it and then it is impossible because your mind cannot hold so much stuff at once.

If you practice this just a few times as you're waiting for something or you are just in your car, then it will be as smooth as butter and you will enjoy it!