Alright, let's solve this problem step by step. We have 3926 and 9713 and we're adding them together.

Step 1: We'll start by adding the digits 6 & 3 in column 1 and get 9.

Step 2: We'll start by adding the digits 2 & 1 in column 2 and get 3.

Step 3: We'll start by adding the digits 9 & 7 in column 3 and get 16.
We'll write down the last digit 6 and carry the 1 to the next column.

Step 4: We'll start by adding the digits 3 & 9 in column 4 and get 13.
We'll write down the last digit 3 and carry the 1 to the next column.

So, 3926 + 9713 = 13639.

