Alright, let's solve this problem step by step. We have 280 and 5111 and we're adding them together.

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

Step 2: We'll start by adding the digits 8 & 1 in column 2 and get 9.

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

Step 4: We'll start by adding the digits 0 & 5 in column 4 and get 5.

So, 280 + 5111 = 5391.

