Division - 4

 If you think of it this way like 4 divided by 2 = ? well how much 2's are in 4 2! so 4 divided by 2 equals 2

Multiplication - 3

 So let's say you have a problem that says 4 x 2 = ? Well it's really easy actually add 2 4's together there ya go it's 8 easy see? (this was really short sorry).

Subtracting - 2

 Subtracting is a little bit harder especially with big numbers lets say you were subtracting 5 from 10 also known as 10 - 5 = 5 its not like adding because your taking away not adding so small numbers are pretty easy but big numbers can be be hard like 10,456 - 5,879 that can be hard but it can be easy sometimes, first subtract the ones then subtract the tens then hundreds and thousands. It should be easy from here now!

Adding - 1

Adding is very simple and easy see like 1+1 for example it does not equal eleven it equals 2 because it makes sense that way, 2+2 doesn't equal 22 it equals 4 so that should help and also stay in classes cause they might teach cooler stuff. But lets go onto more complicated questions like 150 + 145 you might think that is hard but no, what is 100 + 100? well whatever it is next what is 50 + 45? now, whatever you got add them together what does it equal it should equal 295. Well now it should be easy for you!