Okay, we are tasked with adding 78 and 6306. Let's begin!

Step 1: We'll start by adding the digits 8 & 6 in column 1 and get 14.
We'll write down the last digit 4 and carry the 1 to the next column.

Step 2: We'll start by adding the digits 7 & 0 in column 2 and get 8.

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

Step 4: We'll start by adding the digits 0 & 6 in column 4 and get 6.

So, 78 + 6306 = 6384.

