Not to worry, we've got 398 and 8860. Let's get to adding them!

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

Step 2: We'll start by adding the digits 9 & 6 in column 2 and get 15.
We'll write down the last digit 5 and carry the 1 to the next column.

Step 3: We'll start by adding the digits 3 & 8 in column 3 and get 12.
We'll write down the last digit 2 and carry the 1 to the next column.

Step 4: We'll start by adding the digits 0 & 8 in column 4 and get 9.

So, 398 + 8860 = 9258.

