OK, let's do this. We've got 2589 and 299 and we're adding them all together.

Step 1: We'll start by adding the digits 9 & 9 in column 1 and get 18.
We'll write down the last digit 8 and carry the 1 to the next column.

Step 2: We'll start by adding the digits 8 & 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 5 & 2 in column 3 and get 8.

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

So, 2589 + 299 = 2888.

