Let's break this down. We're going to add 155312031 and 85635038 together.

Step 1: We'll start by adding the digits 1 & 8 in column 1 and get 9.

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

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

Step 4: We'll start by adding the digits 2 & 5 in column 4 and get 7.

Step 5: We'll start by adding the digits 1 & 3 in column 5 and get 4.

Step 6: We'll start by adding the digits 3 & 6 in column 6 and get 9.

Step 7: We'll start by adding the digits 5 & 5 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 5 & 8 in column 8 and get 14.
We'll write down the last digit 4 and carry the 1 to the next column.

Step 9: We'll start by adding the digits 1 & 0 in column 9 and get 2.

So, 155312031 + 85635038 = 240947069.

