Alright, let's solve this problem step by step. We have 5409 and 1250 and we're adding them together.

Step 1: We'll start by adding the digits 9 & 0 in column 1 and get 9.

Step 2: We'll start by adding the digits 0 & 5 in column 2 and get 5.

Step 3: We'll start by adding the digits 4 & 2 in column 3 and get 6.

Step 4: We'll start by adding the digits 5 & 1 in column 4 and get 6.

So, 5409 + 1250 = 6659.

