We are presented with 1209 and 5071. Let's work out the sum.

Step 1: We'll start by adding the digits 9 & 1 in column 1 and get 10.
We'll write down the last digit 0 and carry the 1 to the next column.

Step 2: We'll start by adding the digits 0 & 7 in column 2 and get 8.

Step 3: We'll start by adding the digits 2 & 0 in column 3 and get 2.

Step 4: We'll start by adding the digits 1 & 5 in column 4 and get 6.

So, 1209 + 5071 = 6280.

