Alright, let's solve this problem step by step. We have 1020 and 6631 and we're adding them together.

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

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

Step 3: We'll start by adding the digits 0 & 6 in column 3 and get 6.

Step 4: We'll start by adding the digits 1 & 6 in column 4 and get 7.

So, 1020 + 6631 = 7651.

