Let's get this math done. We have 8403 and 246 and we're going to add them all together.

Step 1: We'll start by adding the digits 3 & 6 in column 1 and get 9.

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

Step 3: We'll start by adding the digits 4 & 2 in column 3 and get 6.

Step 4: We'll start by adding the digits 8 & 0 in column 4 and get 8.

So, 8403 + 246 = 8649.

