In this tutorial, we are going to learn the shortcut, how to obtain the square of any 2 digit number or 3-digit numbers.In competitive examinations, we often come across questions where we need to obtain the square of number like 1212, 872 etc.
After practising this shortcut, you will how easy it is to obtain the square of any 2 or 3 digit numbers. In order to use this shortcut, is important that you know the squares of all the numbers till 30 at least.
I hope you all remember the square formula : (a + b)2 = a2 + b2 + 2ab
Let’s modify the formula to look something like this :
Let’s understand the steps with an example. Let’s say we want to compute 212.
Step 1 : Break the number such that a=2, and b=1
Step 2 : Compute a2, ab and b2 and write as shown in the updated formula
Step 3 : Notice the second row of the formula is obtained by just repeating the middle term ab of the first row.
Very easy right 🙂
Example : Let’s take another example. Let’s say we want to compute 562. In this a=5 and b=6. Notice the carry-forward in each step.
Example : Let us consider a 3 – digit number 122. Can you obtain the square of 122 ?
No matter, how big the number is, as long as you are able to break the numbers in a and b and you know a2 and b2, you can obtain the square of the number very easily.
If you know the squares of all the numbers till 30, it is possible to use the above shortcut to obtain the squares of all the numbers till 300 in under 15 seconds.
Exercise : Can you obtain the squares of :
Please contact me if some point in the tutorial is not clear. I would be glad to help.