Alright, let's solve this problem step by step. We have 2103 and 6123 and we're adding them together.

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

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

Step 3: We'll start by adding the digits 1 & 1 in column 3 and get 2.

Step 4: We'll start by adding the digits 2 & 6 in column 4 and get 8.

So, 2103 + 6123 = 8226.

