Okay, we are tasked with adding 1265 and 6613. Let's begin!

Step 1: We'll start by adding the digits 5 & 3 in column 1 and get 8.

Step 2: We'll start by adding the digits 6 & 1 in column 2 and get 7.

Step 3: We'll start by adding the digits 2 & 6 in column 3 and get 8.

Step 4: We'll start by adding the digits 1 & 6 in column 4 and get 7.

So, 1265 + 6613 = 7878.

