We've got two numbers: 784 and 1215. Let's find their sum.

Step 1: We'll start by adding the digits 4 & 5 in column 1 and get 9.

Step 2: We'll start by adding the digits 8 & 1 in column 2 and get 9.

Step 3: We'll start by adding the digits 7 & 2 in column 3 and get 9.

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

So, 784 + 1215 = 1999.

