We are presented with 666 and 8122. Let's work out the sum.

Step 1: We'll start by adding the digits 6 & 2 in column 1 and get 8.

Step 2: We'll start by adding the digits 6 & 2 in column 2 and get 8.

Step 3: We'll start by adding the digits 6 & 1 in column 3 and get 7.

Step 4: We'll start by adding the digits 0 & 8 in column 4 and get 8.

So, 666 + 8122 = 8788.

