What do you call a pair of numbers that describes a rate or a comparison?

A pair of numbers that describes a rate or a comparison is known as a ratio. Ratios compare two quantities and express their relationship to one another, indicating how much of one quantity exists in relation to another. For example, if there are 2 apples and 3 oranges, the ratio of apples to oranges can be written as 2 to 3 or 2:3. This clearly shows how many apples there are for every three oranges, making it an effective way to convey comparative information.

While a fraction also involves two numbers, it specifically represents a part of a whole, rather than a direct comparison between two distinct quantities. A percentage is a fraction expressed out of 100, providing a specific way to represent a ratio but not directly illustrating the comparative relationship as a ratio does. A proportion, on the other hand, refers to an equation that states two ratios are equal, focusing further on the relationship rather than simply describing it, which distinguishes it from a basic ratio.