No problem, let's work through this together. We're starting with 790 and 649 and adding them all up.

Step 1: We'll start by adding the digits 0 & 9 in column 1 and get 9.

Step 2: We'll start by adding the digits 9 & 4 in column 2 and get 13.
We'll write down the last digit 3 and carry the 1 to the next column.

Step 3: We'll start by adding the digits 7 & 6 in column 3 and get 14.
We'll write down the last digit 4 and carry the 1 to the next column.

So, 790 + 649 = 1439.

