Ready to do some math? We're starting with 3504 and 9001 and adding them up.

Step 1: We'll start by adding the digits 4 & 1 in column 1 and get 5.

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

Step 3: We'll start by adding the digits 5 & 0 in column 3 and get 5.

Step 4: We'll start by adding the digits 3 & 9 in column 4 and get 12.
We'll write down the last digit 2 and carry the 1 to the next column.

So, 3504 + 9001 = 12505.

