Fractions are ratios that’s why we call them rational numbers (ratio numbers). If you think about fractions as ratios, how does this help you to understand them?

# Category: Ratio

# Birthday

In a class of 23 students, the chances are fifty-fifty that two of them will have the same birthday. Now that may sound impossible since there are 365 different possibilities, but we can use probability to see that it is true.

# Air Pollution

This chart recently came out from the American Lung Association about air pollution in the United States. How would you present this data to Congress to get them to deal with this serious problem?

# Powers of Ten

Picturing exponential growth, powers of 10, can be hard for any of us to imagine. The spreadsheet has the flexibility to enable us to explore the powers of 10 and to get a visual image of them. We can see the difference in shape between odd and even powers, and get a sense of the speed of exponential growth. We use powers of ten to gain a sense not only of big numbers but of how big spreadsheets can be.

# Moore’s Law

It was one of the most amazing visions of the future ever made. In 1965 Gordon Moore, one of the founders of Intel, proposed a law governing the future of computing. He originally proposed that the number of components on a chip would double every year. Later he revised that law to doubling every two years. You can take a look at the real data of CPU development over the past 40 years and see if it in fact has followed Moore’s law and whether it can continue. In the process you will be looking at very large numbers and the effects of exponential growth on something we now live with all the time.