We've got two numbers: 6007 and 392. Let's find their sum.

Step 1: We'll start by adding the digits 7 & 2 in column 1 and get 9.

Step 2: We'll start by adding the digits 0 & 9 in column 2 and get 9.

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

Step 4: We'll start by adding the digits 6 & 0 in column 4 and get 6.

So, 6007 + 392 = 6399.

