Okay, we are given 4251 and 5208. Let's add them up step by step.

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 5 & 0 in column 2 and get 5.

Step 3: We'll start by adding the digits 2 & 2 in column 3 and get 4.

Step 4: We'll start by adding the digits 4 & 5 in column 4 and get 9.

So, 4251 + 5208 = 9459.

