If you memorized first 25 squares (e.g. from my previous video), now with this trick you will be able to get two last digits of any square in 2 or 3 seconds!
This will allow you calculate squares much faster as now you will need only rough estimation to get the precise result.
In this video I also show how to use it on squares of number 25-40. In the following videos I will cover method for remaining numbers up to 100.
Calculating squares quickly also helps you use Method of Squares for multiplying two numbers, covered in my other videos.
On my channel you will find other videos with fast calculation methods, but also with logic puzzles and problem solving techniques.