Alright, let's solve this problem step by step. We have 5257 and 20 and we're adding them together.

Step 1: We'll start by adding the digits 7 & 0 in column 1 and get 7.

Step 2: We'll start by adding the digits 5 & 2 in column 2 and get 7.

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

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

So, 5257 + 20 = 5277.

