Let's break this down. We're going to add 2415 and 6441 together.

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

Step 2: We'll start by adding the digits 1 & 4 in column 2 and get 5.

Step 3: We'll start by adding the digits 4 & 4 in column 3 and get 8.

Step 4: We'll start by adding the digits 2 & 6 in column 4 and get 8.

So, 2415 + 6441 = 8856.

