Android and iphone app to calculate various engineering terms needed

Hi there, I am looking for someone to develop an app for both android and iphone. This app will calculate various terms in mechanical engineering. For example..and just as an example: x = ?( v + v )t Here X is the displacement..so if the user wants to calculate the displacement, the app asks for the values of v and vo and t. It then displays the value of displacement as calculated. The user can now save or print/email the result. The user should have the option of manually enter the values or browse and enter from a dataset/table that is built in (for certain variables) I will supply the equations, the datasets all other data to calculate the terms I need in the app. I will need you to design the app gui..should be absolutely beautiful and functional. I envision on app startup it would show a home button and 4 other buttons (categories). Then when you click on any button, it will go to a screen with other categories (subcategories), then choose the calculation you need to do, then start entering the variables (manually or browse through), then hit calculate and the result should be displayed, the user can now print or email the report that shows all the values entered, the name of the project, the time and the result with a sketch. I expect the programming part to be starighforward but the typing of all the tables and data into the app's core (for lookup by users) to be the most time consuming and critical task for this project..may be it is easier thean what I think. So, all in all, I basically need a custom calculator that will calculate dertain engineering terms. I expect about 20-25 equations. Please advise on your costs and time frame for development. Thanks.