No problem, let's work through this together. We're starting with 5998 and 4687 and adding them all up.

Step 1: We'll start by adding the digits 8 & 7 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 & 8 in column 2 and get 18.
We'll write down the last digit 8 and carry the 1 to the next column.

Step 3: We'll start by adding the digits 9 & 6 in column 3 and get 16.
We'll write down the last digit 6 and carry the 1 to the next column.

Step 4: We'll start by adding the digits 5 & 4 in column 4 and get 10.
We'll write down the last digit 0 and carry the 1 to the next column.

So, 5998 + 4687 = 10685.

