Okay, we are tasked with adding 6840 and 4037. Let's begin!

Step 1: We'll start by adding the digits 0 & 7 in column 1 and get 7.

Step 2: We'll start by adding the digits 4 & 3 in column 2 and get 7.

Step 3: We'll start by adding the digits 8 & 0 in column 3 and get 8.

Step 4: We'll start by adding the digits 6 & 4 in column 4 and get 10.
We'll write down the last digit 0 and carry the 1 to the next column.

So, 6840 + 4037 = 10877.

