Let's solve this addition problem. We have 7581 and 308, and we need to add them together.

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

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

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

Step 4: We'll start by adding the digits 7 & 0 in column 4 and get 7.

So, 7581 + 308 = 7889.

