We have numbers 7215 and 1020. Let's start adding them together.

Step 1: We'll start by adding the digits 5 & 0 in column 1 and get 5.

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

Step 3: We'll start by adding the digits 2 & 0 in column 3 and get 2.

Step 4: We'll start by adding the digits 7 & 1 in column 4 and get 8.

So, 7215 + 1020 = 8235.

