what is 3+1

3 + 1 can be turned into:

(1 + 1 + 1) + 1

Using distributive property, we get:

1 + 1 + 1 + 1

Then we count how many 1's we have:

1 + 1 + 1 + 1

1.   2.   3.   4.

We have 4 1's, so the answer is 4.

Of course, this is simple addition, and you probably already have this memorized.