How do you get 12 by using the numbers nine and three and two and six but you can only use each number once in each operation which is adding subtracting multiplying and division only once number

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 the scale factor between two circles is 2x/5y what is the ratio of their areas?

Timmy uses 1 1 2 cups of sugar for every 2 gallons of lemonade he makes. how many cups of sugar would timmy use if he makes 13 gallons of lemonade?