Let's break this down. We're going to add 6211 and 7713 together.

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

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 2 & 7 in column 3 and get 9.

Step 4: We'll start by adding the digits 6 & 7 in column 4 and get 13.
We'll write down the last digit 3 and carry the 1 to the next column.

So, 6211 + 7713 = 13924.

