Alright, let's solve this problem step by step. We have 35 and 6339 and we're adding them together.

Step 1: We'll start by adding the digits 5 & 9 in column 1 and get 14.
We'll write down the last digit 4 and carry the 1 to the next column.

Step 2: We'll start by adding the digits 3 & 3 in column 2 and get 7.

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

Step 4: We'll start by adding the digits 0 & 6 in column 4 and get 6.

So, 35 + 6339 = 6374.

