Q How do I create an input file of numbers on the maths server? A You can do this through the vi editor, the same as how you create a new .c file. Simply type 'vi numbers' and then insert some numbers (hit 'i' on keyboard). You can then save the file and quit the editor with ':wq'. You will then find the file 'numbers' in your current directory. Q What does the syntax &x mean in scanf? A When you declare a variable say 'int x' this assigns a part of the computer's memory to store an integer labelled 'x'. The syntax for scanf requires you give it the memory address of the variable, as opposed to just the label 'x'. This is given by '&x' . You can try print this out to see what it looks like with printf("%p\n", &x). Q How do I check if a number is odd or even? A The modulo operator % can be used to determine the remainder left over when one number is divided by another. For example, 7 % 3 = 1 as 7 = 2 * 3 + a remainder of 1. You should be able to use this to determine if the number is odd or even.