# Mathematics in Non-math Courses

In introductory courses such as chemistry, economics, political science, and psychology, you will often see discussions of examples and topics that require an understanding of concepts in mathematics such as decimals, percents, ratios, and proportions. While the examples below are taken directly from different economics textbooks, they demonstrate the kinds of skills that you will be required to use in many non-math introductory courses.

### Example

 Rising divorce rates and births out of wedlock have reduced married couples as a percentage of total families from 70% in 1970 to 60% in 1990. Further, the percentage of married-couple households in which the wife was working increased by roughly 50% over the last two decades. These trends mean... From: Byrns, R. T. and Stone, G. W. (1995) Microeconomics (p. 370).New York: Harper Collins College Publishers.

The paragraph above is part of a discussion on the economic impact of decline in married couple households. As we can see, the use of percentage is central to this discussion, and without a full understanding of percents this discussion would be difficult to fully understand.

### Example

 The ratio of new deposits to the increase in reserves is called the money-supply multiplier. In the simple case analyzed here, the money-supply multiplier is equal to: From: Samuelson P. A. & Nordhaus, W. D. (1995) Macroeconomics (p. 169). New York: McGraw-Hill.

Ratios and decimals can be found in discussion in text books. They also often occur in conjunction with the use of percents. The paragraph above came from a discussion on the money-supply multiplier which uses ratios and proportions.

Decimals, percents, ratios, and proportions come up again and again in both everyday and academic life. Whether they are used in discussions as the ones shown above, or in tables, charts, and graphs (This will be discussed in Book III of this series.), understanding how to working with these concepts is important to your success in your introductory courses.

In many introductory courses you will come across decimals, percents, ratios, and proportions in discussions and be asked to perform calculations using these. This book provides you with the math skills you will need for these courses.

The skills you will learn in this review are: