We have numbers 8784 and 5100. Let's start adding them together.

Step 1: We'll start by adding the digits 4 & 0 in column 1 and get 4.

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

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

Step 4: We'll start by adding the digits 8 & 5 in column 4 and get 13.
We'll write down the last digit 3 and carry the 1 to the next column.

So, 8784 + 5100 = 13884.

