We are presented with 3508 and 3165. Let's work out the sum.

Step 1: We'll start by adding the digits 8 & 5 in column 1 and get 13.
We'll write down the last digit 3 and carry the 1 to the next column.

Step 2: We'll start by adding the digits 0 & 6 in column 2 and get 7.

Step 3: We'll start by adding the digits 5 & 1 in column 3 and get 6.

Step 4: We'll start by adding the digits 3 & 3 in column 4 and get 6.

So, 3508 + 3165 = 6673.

