Let's break this down. We're going to add 7018 and 71 together.

Step 1: We'll start by adding the digits 8 & 1 in column 1 and get 9.

Step 2: We'll start by adding the digits 1 & 7 in column 2 and get 8.

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

Step 4: We'll start by adding the digits 7 & 0 in column 4 and get 7.

So, 7018 + 71 = 7089.

