Maths Tricks

Trick 1 : Multiply any two numbers from 11 to 20 in your head.

Take 15 × 13 for example… Place the larger no. first in your mind and then do something like this Take the larger no on the top and the second digit of the smaller no. in the bottom.
15
3
The rest is quite simple. Add 15+3 = 18 . Then multiply 18 × 10 = 180 …
Now multiply the second digit of both the no.s (ie; 5 × 3 = 15) Now add 180 + 15. Here is the answer 180 + 15 = 195 . Think over it. This is a simple trick. It will help you a lot.

Trick 2 : Multiply any two digit number with 11.
This trick is much simpler than the previous one and it is more useful too. Let the number be 27 . Therefore 27 × 11
Divide the number as 2 _ 7
Add 2+ 7 = 9
Thus the answer is 2 9 7
Wasn’t this one simple. But there is one complication. If you take a number like 57 Thus 5_7 x 11
Divide the number as 5 _ 7
Add 5 + 7 = 12
Now add 1 to 5 and place 2 in the middle so the answer is 5+1_2 _7 = _627
Thus the answer is 627.

Trick 3: Square a two digit number ending in five. This one is as easy as the previous ones but you have to pay a little more attention to this one . Read carefully :Let the number be 35
35 × 35
Multiply the last digits of both the numbers ; thus ___ 5 × 5 = 25
now add 1 to 3 thus 3 + 1 = 4
multiply 4 × 3 = 12
thus answer 1225

You will have to think over this one carefully.As 5 has to come in the end so the last two digits o the answer will be 25 . Add 1 to the first digit and multiply it by the original first digit . Now this answer forms the digits before the 25. Thus we get an answer.
Trick 4 : Square any two digit number.

Suppose the number is 47 . Look for the nearest multiple of 10 . ie; in this case 50. We will reach 50 if we add 3 to 47. So multiply (47+3) x (47-3) = 50 × 44 = 2200 This is the 1st interim answer.

We had added 3 to reach the nearest multiple of 10 that is 50 thus 3x 3 = 9 This is the second interim answer.
The final answer is 2200 + 9 = 2209 … Practice This one on paper first.