Not to worry, we've got 3963 and 2682. Let's get to adding them!

Step 1: We'll start by adding the digits 3 & 2 in column 1 and get 5.

Step 2: We'll start by adding the digits 6 & 8 in column 2 and get 14.
We'll write down the last digit 4 and carry the 1 to the next column.

Step 3: We'll start by adding the digits 9 & 6 in column 3 and get 16.
We'll write down the last digit 6 and carry the 1 to the next column.

Step 4: We'll start by adding the digits 3 & 2 in column 4 and get 6.

So, 3963 + 2682 = 6645.

