Monday, January 4, 2010

Squaring a no ending with 5

In this post,let s learn how to square a number that ends with the digit '5'.
Using examples to learn a method is always easy, so let s consider the squaring of the no '45'.

For all the nos ending with 5, the squared resultant no will have 25 as its last 2 digits. So, resultant must in the pattern _____25, what comes in the blank is calculated as follows. Remove the '5' from '45', we are left with '4', multiply it with its consecutive no, being '5', which gives 4*5=20. This '20' is filled in the above blank, hence giving the resultant to be 2025 !!!
Another example : 75
Pattern : ____ 25
7*8=56, hence resultant would be 5625.

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