Not to worry, we've got 4230 and 2379. Let's get to adding them!

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 3 & 7 in column 2 and get 10.
We'll write down the last digit 0 and carry the 1 to the next column.

Step 3: We'll start by adding the digits 2 & 3 in column 3 and get 6.

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

So, 4230 + 2379 = 6609.

