more questions on digital electronics

Given 2 4 bit nos, A= 1001, b= 1100

• HOW DO YOU ExOR THEM using minimum number of gates?
• how do you nand them?
• how do your or them?
  

2. given a 4:1 functional generator how do you resolve a 5:1 functional generator using only 4:1 funtional generators? what happens to the unused inputs?

3. using a 4:1 mux how many 4:1 mux do you need to design a 8:1 mux?