Need help in Options

Hi All,

In the menu,

Catalogue -> Products-> Options -> I have added three "Quantity".
But for pricing it provide me option to enter the price which will get added to the basic price given for that product.
While buying it is a confusion for customers to select the quantity, because they need to do the math calculation of adding the basic price with the extra price mentioned for the other quantity.

Please help me and let me know if there any other option in opencart to display different price for different quantity for the same product.

Thanks&Regards
Baskaran V