Okay, we are given 1089 and 2510. Let's add them up step by step.

Step 1: We'll start by adding the digits 9 & 0 in column 1 and get 9.

Step 2: We'll start by adding the digits 8 & 1 in column 2 and get 9.

Step 3: We'll start by adding the digits 0 & 5 in column 3 and get 5.

Step 4: We'll start by adding the digits 1 & 2 in column 4 and get 3.

So, 1089 + 2510 = 3599.

