Let's solve this addition problem. We have 4001 and 980, and we need to add them together.

Step 1: We'll start by adding the digits 1 & 0 in column 1 and get 1.

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 0 & 9 in column 3 and get 9.

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

So, 4001 + 980 = 4981.

