Let's break this down. We're going to add 5259 and 23 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 5 & 2 in column 2 and get 8.

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, 5259 + 23 = 5282.

