What is square of 42 without actual multiplication.
Given, the number is 42.
We need to square the number 42.
Step1: expand the number
42=(40+2)
422=40+22
Step 2:using identity, (a+b)2=a2+b2+2ab
where a=40 and b=2
Now, we get;
422=40+22422=402+22+2×40×2422=1600+4+160422=1764
Therefore, the square of 42 is 1764.
How to find the square of 31 without actual multiplication?