Let's break this down. We're going to add 4108 and 1581 together.

Step 1: We'll start by adding the digits 8 & 1 in column 1 and get 9.

Step 2: We'll start by adding the digits 0 & 8 in column 2 and get 8.

Step 3: We'll start by adding the digits 1 & 5 in column 3 and get 6.

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

So, 4108 + 1581 = 5689.

