We are presented with 6601 and 3922. Let's work out the sum.

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

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

Step 3: We'll start by adding the digits 6 & 9 in column 3 and get 15.
We'll write down the last digit 5 and carry the 1 to the next column.

Step 4: We'll start by adding the digits 6 & 3 in column 4 and get 10.
We'll write down the last digit 0 and carry the 1 to the next column.

So, 6601 + 3922 = 10523.

