We are presented with 9150 and 8700. Let's work out the sum.

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

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

Step 3: We'll start by adding the digits 1 & 7 in column 3 and get 8.

Step 4: We'll start by adding the digits 9 & 8 in column 4 and get 17.
We'll write down the last digit 7 and carry the 1 to the next column.

So, 9150 + 8700 = 17850.

