Let's solve this addition problem. We have 8599 and 2836, and we need to add them together.

Step 1: We'll start by adding the digits 9 & 6 in column 1 and get 15.
We'll write down the last digit 5 and carry the 1 to the next column.

Step 2: We'll start by adding the digits 9 & 3 in column 2 and get 13.
We'll write down the last digit 3 and carry the 1 to the next column.

Step 3: We'll start by adding the digits 5 & 8 in column 3 and get 14.
We'll write down the last digit 4 and carry the 1 to the next column.

Step 4: We'll start by adding the digits 8 & 2 in column 4 and get 11.
We'll write down the last digit 1 and carry the 1 to the next column.

So, 8599 + 2836 = 11435.

