Okay, we are given 7800 and 128. Let's add them up step by step.

Step 1: We'll start by adding the digits 0 & 8 in column 1 and get 8.

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

Step 3: We'll start by adding the digits 8 & 1 in column 3 and get 9.

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

So, 7800 + 128 = 7928.

