One-quarter of sum of half of x and six

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?

You are at a restaurant and owe $38 for your meal. you want to leave a 20% tip. how much will your tip be?

Find an bif a = {3, 6, 9, 12) and b = {2, 4, 6, 8, 10).