MAth please help ASAP

International calls require the use of a country code. many country codes a 3-digit numbers. country codes do not begin with a 0 or 1. there are no restrictions on the second and third digits. how many different 3-digit country codes are possible?

If g^-1(x) is the inverse of g (x) which statement must be true

Perry observes the opposite parallel walls of a room in how many lines do the plains containing the walls intersect