Let's break this down. We're going to add 3510 and 4978 together.

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 1 & 7 in column 2 and get 8.

Step 3: We'll start by adding the digits 5 & 9 in column 3 and get 14.
We'll write down the last digit 4 and carry the 1 to the next column.

Step 4: We'll start by adding the digits 3 & 4 in column 4 and get 8.

So, 3510 + 4978 = 8488.

