Write a C program which will run in Unix multiprocessor system

This machine has exactly 3 processors and your program is supposed to read two integer values A and B and compute 3 different results: 

A*B, A-B and A+B. Execute all three operations in parallel. The main mission is to write the program (only 1 program) that "forks" two other processes in order to do all three operations simultaneously and display the results in the screen. Use CIGWIN to run and verify the code or any other Unix-like system.