We are presented with 8408 and 6045. Let's work out the sum.

Step 1: We'll start by adding the digits 8 & 5 in column 1 and get 13.
We'll write down the last digit 3 and carry the 1 to the next column.

Step 2: We'll start by adding the digits 0 & 4 in column 2 and get 5.

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

Step 4: We'll start by adding the digits 8 & 6 in column 4 and get 14.
We'll write down the last digit 4 and carry the 1 to the next column.

So, 8408 + 6045 = 14453.

