Alright, let's solve this problem step by step. We have 2001 and 2098 and we're adding 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 0 & 9 in column 2 and get 9.

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

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

So, 2001 + 2098 = 4099.

