Here we go! We're going to add 2390 and 4509 together.

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 & 0 in column 2 and get 9.

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

Step 4: We'll start by adding the digits 2 & 4 in column 4 and get 6.

So, 2390 + 4509 = 6899.

