The scale on a map that 5 centimeters = 2 kilometers

Which rational number could be graphed between -4 and -5

Arestaurant offers a $12 dinner special that has 5 choices for an appetizer, 12 choices for an entrée, and 4 choices for a dessert. how many different meals are available when you select an appetizer, an entrée, and a dessert? a meal can be chosen in nothing ways. (type a whole number.)

What is the number 321,000,000 in scientific notation? also what is the number? ?