OK, let's do this. We've got 2005 and 4420 and we're adding them all together.

Step 1: We'll start by adding the digits 5 & 0 in column 1 and get 5.

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

Step 3: We'll start by adding the digits 0 & 4 in column 3 and get 4.

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

So, 2005 + 4420 = 6425.

