Okay, we are tasked with adding 829927046 and 450934359. Let's begin!

Step 1: We'll start by adding the digits 6 & 9 in column 1 and get 15.
We'll write down the last digit 5 and carry the 1 to the next column.

Step 2: We'll start by adding the digits 4 & 5 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 0 & 3 in column 3 and get 4.

Step 4: We'll start by adding the digits 7 & 4 in column 4 and get 11.
We'll write down the last digit 1 and carry the 1 to the next column.

Step 5: We'll start by adding the digits 2 & 3 in column 5 and get 6.

Step 6: We'll start by adding the digits 9 & 9 in column 6 and get 18.
We'll write down the last digit 8 and carry the 1 to the next column.

Step 7: We'll start by adding the digits 9 & 0 in column 7 and get 10.
We'll write down the last digit 0 and carry the 1 to the next column.

Step 8: We'll start by adding the digits 2 & 5 in column 8 and get 8.

Step 9: We'll start by adding the digits 8 & 4 in column 9 and get 12.
We'll write down the last digit 2 and carry the 1 to the next column.

So, 829927046 + 450934359 = 1280861405.

