Not to worry, we've got 678 and 2321. Let's get to adding them!

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

Step 2: We'll start by adding the digits 7 & 2 in column 2 and get 9.

Step 3: We'll start by adding the digits 6 & 3 in column 3 and get 9.

Step 4: We'll start by adding the digits 0 & 2 in column 4 and get 2.

So, 678 + 2321 = 2999.

