how can i calculate this!! I have the answers i just dont know how to do them

Calculate the following parameters of a hypothetical computer system with these features: a) HEX notation b) IR = OPCode + Mem Addr; c)IR=16bits; d) PC = 3 HEX digits; and e) Mem word size = Data (unsigned integer) = IR

answers: Number of different opcodes: 16 Mem size in bytes: 8192 Mem range: [000 - FFF] Data range: [0000 - FFFF]