Not to worry, we've got 298 and 991. 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 9 & 9 in column 2 and get 18.
We'll write down the last digit 8 and carry the 1 to the next column.

Step 3: We'll start by adding the digits 2 & 9 in column 3 and get 12.
We'll write down the last digit 2 and carry the 1 to the next column.

So, 298 + 991 = 1289.

