No problem, let's work through this together. We're starting with 8440 and 6700 and adding them all up.

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

Step 2: We'll start by adding the digits 4 & 0 in column 2 and get 4.

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

Step 4: We'll start by adding the digits 8 & 6 in column 4 and get 15.
We'll write down the last digit 5 and carry the 1 to the next column.

So, 8440 + 6700 = 15140.

