We are presented with 31800861 and 55462472. Let's work out the sum.

Step 1: We'll start by adding the digits 1 & 2 in column 1 and get 3.

Step 2: We'll start by adding the digits 6 & 7 in column 2 and get 13.
We'll write down the last digit 3 and carry the 1 to the next column.

Step 3: We'll start by adding the digits 8 & 4 in column 3 and get 13.
We'll write down the last digit 3 and carry the 1 to the next column.

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

Step 5: We'll start by adding the digits 0 & 6 in column 5 and get 6.

Step 6: We'll start by adding the digits 8 & 4 in column 6 and get 12.
We'll write down the last digit 2 and carry the 1 to the next column.

Step 7: We'll start by adding the digits 1 & 5 in column 7 and get 7.

Step 8: We'll start by adding the digits 3 & 5 in column 8 and get 8.

So, 31800861 + 55462472 = 87263333.

