No problem, let's work through this together. We're starting with 7599 and 3781 and adding them all up.

Step 1: We'll start by adding the digits 9 & 1 in column 1 and get 10.
We'll write down the last digit 0 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 5 & 7 in column 3 and get 13.
We'll write down the last digit 3 and carry the 1 to the next column.

Step 4: We'll start by adding the digits 7 & 3 in column 4 and get 11.
We'll write down the last digit 1 and carry the 1 to the next column.

So, 7599 + 3781 = 11380.

