Find the distance between a and b.

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?

How long must $542 be invested at a rate of 7% to earn $303.52 in interest? in a easier way

Kayaks rent for $35 per day. which expression can you use to find the cost in dollars of renting 3 kayaks for a day?