Alright, let's solve this problem step by step. We have 6475 and 394 and we're adding them together.

Step 1: We'll start by adding the digits 5 & 4 in column 1 and get 9.

Step 2: We'll start by adding the digits 7 & 9 in column 2 and get 16.
We'll write down the last digit 6 and carry the 1 to the next column.

Step 3: We'll start by adding the digits 4 & 3 in column 3 and get 8.

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

So, 6475 + 394 = 6869.

