Part 1 : Easier Method To Find Squares Near 100

Can you solve 105², mentally?

Well, without using my calculator, the answer for 105² is 11025, just in a second.

To find 105² in a smarter way, you need to follow these steps :

  1. 105 is 5 more than 100 (105 – 100 = 5).  So, our first step is to add that 5 to 105 which gives you 110.  This is the first three digits of our answer.
  2. Then square that digit 5 which gives you 25.  This is the last two digits of our answer. (If the answer of the square is more than two digits, we need to carry the first digit of the answer of the square).
  3. And for our last step, just attach this 25  to 110.  Therefore 105²=11025.

This is the easier way to find squares near 100, mentally.

Now, let us try to solve 107².

107 + 7 = 114  (step 1) 

7² = 49 (step 2)

Therefore,

107² = 11449  (step 3)

It is easy, isn’t it?  Now, try 109².

109 + 9 = 118

And

9² = 81

Therefore,

109² = 11881

Ok, now can you solve 112²?

112 + 12 = 124 (112 is 12 more than 100)

12² = 144 (three digits answer for square.  Need to carry the digit 1)

So our answer would be :

112² = 12544

What if the number is near to 100 but less than 100?  For example, what is 95²?  We will learn this in part 2.  It is easy, and infact, maths is so easy, indeed🙂

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Posted on April 13, 2009, in Info Matematik. Bookmark the permalink. Leave a comment.

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