We are presented with 7020 and 729. Let's work out the sum.

Step 1: We'll start by adding the digits 0 & 9 in column 1 and get 9.

Step 2: We'll start by adding the digits 2 & 2 in column 2 and get 4.

Step 3: We'll start by adding the digits 0 & 7 in column 3 and get 7.

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

So, 7020 + 729 = 7749.

