Let's break this down. We're going to add 3813 and 1013 together.

Step 1: We'll start by adding the digits 3 & 3 in column 1 and get 6.

Step 2: We'll start by adding the digits 1 & 1 in column 2 and get 2.

Step 3: We'll start by adding the digits 8 & 0 in column 3 and get 8.

Step 4: We'll start by adding the digits 3 & 1 in column 4 and get 4.

So, 3813 + 1013 = 4826.

