I sent an invention to Harvey Reese. He politely said "No thank you"
His 3 page letter also gave me an idea how to modify my invention to something even better.
I believe Harvey Reese is an honest and very good business man.
Protecting, producing, and profiting from an idea requires hard and smart work.
Presenting an idea to a big company and walking away with a license deal can happen but it is rare.
I recommend reading "Profit From Your Idea" by Richard Stim.
This book is must for any serious inventor.
If you are manufacturing in China The first three rules are:
VOLUME, VOLUME, VOLUME
If you are looking for lower quantities you are better served working locally.
I would be happy to recommend a China rep based in the USA.
He will provide references upon request.
Congratulations on your prototype.
Molding one plastic part is not practical. You may consider machining a part from solid delrin.
Delrin is plastic that is often referred to as a poor man`s nylon.
I have over 20 years experience developing prototypes and would enjoy discussing this project with you.
Can a mathematical formula be patented? Your code my be a trade secret like the formula for Coca Cola. I`m not a lawyer.
Perhaps another approach could be offer your service online for free.
Make it Blackberry friendly.
With enough traffic you would produce revenue with ads from google adsense.
This would generate a continuous stream of income for you.
Tooling up to produce a calculator will only provide a narrow profit from one sale.
An online service would cost less and make more money for you.