Daily Math Problem Contest

I would like a program that will display a daily problem on the homepage of my website. Users will be able to submit answers and have their scores tracked over time. Here are my specific requirements: It should require a simple php command to insert the problem where I want it. I need a password-protected administrative area where I can add problems, remove problems, and view the results (total tries, total correct, and % correct) for each. It should be designed to support one problem per day, so that when I add a problem I pick which day it will be active for. During that day users can answer only that problem. If they have already tried it, a message will be displayed indicating that. I should be able to enter many problems in advance, selecting which days the problem will be active for. Make sure that it is the server reading the date so the user cannot cheat by adjusting the date on his end. The answer to each problem will be a number (positive or negative) with at most 2 decimal places. The program should be able to remove all letters and extra spaces and properly read the answers so that "- 4.60" is the same as "-4.6" and "- 4.60000". All users will see the problem on the homepage and the answer field, but if they are not registered and signed in they will first be taken to a login page. They must register in order to know if their answer was correct, or else they could cheat. To register, a user must supply their name, a username and password, their age, and their email address. Users must be at least 13 years old to register. Once registered, the user will be able to submit answers from the homepage, enter their name and password on the login page, and have their answers stored. They won't be allowed to see if their answer was correct until the next day, to prevent cheating. Users should be able to view a history of the problems they have attempted and whether or not they were successful. They also can see how they rank among all users (for example, 51st out of 200 users). They should be able to see ranks based on total correct and percentage correct among users who have submitted at least 10 problems. From my control panel I will be able to add problems for future days and the problems will automatically become active on that day. I should be able to delete users and edit all statistics for any user. I should be able to see overall statistics about how many students were correct for each problem. I will be happy to provide more details if necessary.