How do you square 2-digit numbers that end with a 0?

Of all the 2-digit numbers that you may need to square, this is certainly the easiest!
Let's try one!  How quickly can you square 40?
To multiply 40 x 40, multiply 4 x 4, then place 2 zeros after the product of 4 x 4.  Very simply, 40 x 40 = 1600.
Here is another one.  What is 70 x 70?  7 x 7 = 49.  Insert both zeros after 49.  70 x 70 = 4900.
The squaring of 2-digit numbers that end in 0 may be a calculation that you will use more often than squaring other numbers.
Use this tip often, and remember to share this with a friend!