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Showing posts with label Number Tricks. Show all posts
Showing posts with label Number Tricks. Show all posts

### Maths Tip and Tricks: Multiply Up to 20X20 In your mind

In a 5 minutes everyone can learn to quickly multiply upto 20x20 in your mind. With this Mathematical trick, you will be able to multiply any two numbers from 11 to 19 in your mind quickly, without the use of a paper or pen and a calculator.

I will assume that you know your multiplication table reasonably well up to 10x10.

Try this this few example:

Step one: Make 15 x 13 for an example.
Step two: Always place the bigger numbe8r of the two on top in your mind.
Step three: Then draw the shape of Africa mentally so it covers the 15 and the 3 from the 13 below. Those covered numbers are all you need.
Step four: First add 15 + 3 = 18
Step five: Add a zero behind it (multiply by 10) to get 180.
Step Six: Multiply the covered lower 3 x the single digit above it the "5" (3x5= 15)
Step seven: Add 180 + 15 = 195.

That was the trick! isn't that easy? Practice this on paper first!

### Back to the same number 7

This maths trick to me one of my friend. It is very funny!
It is very simple:

Ask your friends to remember keep in mind any number. It is always better a two digit number if don't have pen of pencil and paper with you. Now ask him to double that. Add 5 to it. Add 12 more to it and subtract 3 and divide by 2. Now subtract the original number  which he was remembering his mind from the above result. Now see the result! it is always 7.

with one example we see how this work!

[first we did] - Let us consider the number: 10

[second we did] - Doubling it, we get: 20

[Third we did] - Now adding 5 and 12 successively, we get: 25 & 37

[Fourth we did] - Subtracting 3 from the above yields: 34

[Fifth we did] - Dividing the above number by 2 would make: 17

[Six we did ] - Subtracting 10 (which was the original number) from the above gives: 7

How funny! enjoy!