Alright, let's solve this problem step by step. We have 3121 and 3048 and we're adding them together.

Step 1: We'll start by adding the digits 1 & 8 in column 1 and get 9.

Step 2: We'll start by adding the digits 2 & 4 in column 2 and get 6.

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

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

So, 3121 + 3048 = 6169.

