Ready to do some math? We're starting with 1000 and 6999 and adding them up.

Step 1: We'll start by adding the digits 0 & 9 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 & 9 in column 3 and get 9.

Step 4: We'll start by adding the digits 1 & 6 in column 4 and get 7.

So, 1000 + 6999 = 7999.

