I really need help with this computer science question.?

You failed to mention the language, but it looks like Java. And Yahoo! Answers is not the place for programming questions, head over to stackoverflow.com instead. But be sure to ask specific questions, no one is going to do homework for you. I'm only a hobbyist programmer, not even in high school yet, and that ignment looks trivial to me. Put some more effort into it -- think through it, plan out how you will organise the functionality. Think through the steps your program will have to take. Go through the ignment and decide what you needs to happen first. Then implement that. You're on the right track with your NumberOperations, first write the methods that your program will use. Break it up into smaller steps like that.