OK, let's do this. We've got 1808 and 3091 and we're adding them all together.

Step 1: We'll start by adding the digits 8 & 1 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 8 & 0 in column 3 and get 8.

Step 4: We'll start by adding the digits 1 & 3 in column 4 and get 4.

So, 1808 + 3091 = 4899.

