No problem, let's work through this together. We're starting with 1287 and 6249 and adding them all up.

Step 1: We'll start by adding the digits 7 & 9 in column 1 and get 16.
We'll write down the last digit 6 and carry the 1 to the next column.

Step 2: We'll start by adding the digits 8 & 4 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 2 & 2 in column 3 and get 5.

Step 4: We'll start by adding the digits 1 & 6 in column 4 and get 7.

So, 1287 + 6249 = 7536.

