Question

I am doing 4th grade number sense are there any cool math tricks or short cuts that would be good for me to know.

Answer 1

what kind of questions are you doing?

Answer 2

here is a neat one:
multiply any number by 11
e.g. 45821 x 11 = 504031

starting from the right, add up all the digits in the odd positions
1+0+0 = 1
now add up the ones in the even positions
3+4+5 = 12
What is the difference between them ?
I will always be a multiple of 11, that is, 11 22 33 etc
The difference could also be zero, zero is considered a multiple of 11.