Develop and Install a custom calculator on my website

I need a freelancer to develop a simple tool that my customers can use on my website to calculate their marks. Background: We are a tutoring centre in Australia, that tutors kids in order to finish High School and gain entry into University. In Australia, Year 12 High school students sit an exam called the HSC, you sit an exam for the subjects you are studying, and the government will collect all the results and give each student an "ATAR" an ATAR is a number between 0 and 99.95. With increments of 0.05. The higher the number, the better. I need a freelancer to: -Develop a program of sort, where students can select the subjects they are studying, input their marks into the calculator, and an "ATAR" being generated. Once this has been developed, you have to install it onto my website, so I need a freelancer to work from the begining, right to the end where customers can start using it, this is what you will be bidding for. Other websites that have this calculator can be found here, so you can see how its used: [login to view URL] [login to view URL] [login to view URL] [login to view URL] My website for reference is here: [login to view URL] I have attached an excel document that I downloaded from a website that can calculate the ATAR. The formulars and everything is on it. However its from the 2011 course, below you will see the data for the 2016 year which is what I need. The data you need for each subject to calculate the results can be found here: [login to view URL] Page 35 - 39