Total calculation is not working properly

Also one of my products (combination pizza $2.00) is adding wrong in the calculation total.

The problem is with the value assigned to the drop down options. The "Combination" is $2.00 per slice. In the options, it shows that it is $1.50 per slice. 

1. Select the "Combination" field and then click the options or gear icon.

2. You'll see the drop down properties will appear. Go to "Surveying" tab and then change the "Calculation Values". Please replace it with 0, 2, 4, 6.

3. Click the "Save Changes" button when you're done.

Hope that helps. If you need further help, let us know. Thank you.