Problem 4. (a) Formulate Euler's Theorem. (b) Formulate Euler's product formula for $(n). Find (100) and (1125) (c) Apply Euler's Theorem to find the last two digits of 113003. Make all steps of your reasoning clear. (d) Show that 4 is not a primitive root modulo 9 and that 5 is a primitive root modulo 9