Let's break this down. We're going to add 4011 and 3564 together.

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

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

Step 3: We'll start by adding the digits 0 & 5 in column 3 and get 5.

Step 4: We'll start by adding the digits 4 & 3 in column 4 and get 7.

So, 4011 + 3564 = 7575.

