Let's solve this addition problem. We have 8004 and 1541, and we need to add them together.

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

Step 2: We'll start by adding the digits 0 & 4 in column 2 and get 4.

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 8 & 1 in column 4 and get 9.

So, 8004 + 1541 = 9545.

