A ratio compares two numbers in order. Ratios are written with a colon, like this:


The order of numbers in a ratio is important. The ratio 4:3 expresses a different relationship than the ratio 3:4 does.

The units of measurement that each of the two numbers expresses is important too. The two numbers in a ratio do not have to have the same units. One chicken to every pot (1 chicken:1 pot) is a ratio. Saying that one British Pound is worth about 1.5 US dollars (1 GBP:1.5 USD) is another ratio.

In some cases, it can be convenient to express ratios all in the same units, for example, the ratio of 9 cups to 16 cups may be written in two ways: with a colon 9:16 or as a common fraction 9/16. The fraction 9/16 is another way of saying 9 divided by 16.

The two numbers in a fraction are referred to so often that they have been given names. The top number in a fraction is the numerator and the bottom number is the denominator:

numerator / denominator

A fraction is another way of expressing one number divided by another. What is 24/56? You can take out a calculator and enter

24 / 56 = 0.42857

Incidentally, if you wanted to know what percent this fraction represented, simply multiply the number by 100, or move the decimal two places to the right.

Video Tutorials

Interactive Quiz

© 2015 Regents of the University of Minnesota. All rights reserved. The University of Minnesota is an equal opportunity educator and employer. Privacy Statement