Alright, let's solve this problem step by step. We have 39 and 103 and we're adding them together.

Step 1: We'll start by adding the digits 9 & 3 in column 1 and get 12.
We'll write down the last digit 2 and carry the 1 to the next column.

Step 2: We'll start by adding the digits 3 & 0 in column 2 and get 4.

Step 3: We'll start by adding the digits 0 & 1 in column 3 and get 1.

So, 39 + 103 = 142.

