Fractions, Decimals, and Percents

Let s say three of eight slices of a pizza have been eaten. What part of the pizza remains If a sprinter runs a 40-yard dash in more than four seconds but less than five seconds, how can we represent the sprinter s exact time A student answers 22 of 25 test questions correctly. How can we express the student s grade as a percent on the test  

It s tough to get through a day without coming across any fractions, decimals, or percents. This book will teach you how to handle every common situation involving parts of numbers (and even a few uncommon ones). 

The skills covered in each chapter build on the skills taught in the preceding chapters. If you jump right into mixed numbers and find yourself unsure of how to take the reciprocal of a fraction, move back a chapter or two. This book does not assume you have any knowledge of fractions, decimals, or percents. Everything you need to know is found on these pages. 

you ve obviously cracked open the cover of this book if you re reading these words. But let s take a quick look at what is lurking in the other chapters. This book includes  

As you work through this book, you ll notice that the chapters are sprinkled with all kinds of helpful tips and icons. Look for these icons and the tips they provide. They include  

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This chapter starts out by showing you how to do the computations needed for solving probability problems. (If you need a more thorough review of the relationships between fractions, decimals, and percents, and how to change from one to another, refer to Chapter 5.) In this chapter, you use the percentages to make the predictions. And you see what the odds are that you ll just love this topic. 

We can now use percents to handle everyday situations, such as leaving a tip or finding simple interest. You ve seen how to work with fractions, decimals, and percents. In the next chapter, well put all three together, converting and comparing among them. 

Those numbers were almost equal. It wasn t until we reached the last (rightmost) decimal place that we were able to determine which number was greater. Sometimes, when comparing fractions, decimals, and percents, we will find two values that are equal. 

We order fractions, decimals, and percents just as we ordered decimals in Chapter 7, because we convert fractions and percents to decimals before comparing and ordering them. Given a set of fractions, decimals, or percents,... 

Given a fraction, decimal, or percent, we can now turn any one of the three into the other two. Having learned how to perform every major operation with fractions, decimals, and percents, you re ready for the posttest. 

After completing the posttest, check your answers. Explanations are provided for every answer, along with the chapter in which the skill being tested is taught. Compare your score on the posttest to your score on the pretest. Did you improve Did you learn from any mistakes you made in the pretest The posttest can help you identify which areas you have mastered and which areas you need to practice. Return to the chapters that cover the topics that are tough for you until those topics become your strengths. You ll be able to ace the pretest, the posttest, and any other test on fractions, decimals, and percents. 

Now that you have reviewed fractions, decimals, and ratios in previous chapters, you are ready to tackle the most common ratio— the percent. The word percent means literally out of one hundred percents compare numerical data to 100. Percent problems are so common that an entire chapter is devoted to this concept. Before you begin learning and reviewing percent, take a few minutes to take this ten-question Benchmark Quiz. These questions are similar to the type of questions that you will find on important tests. When you are finished, check the answer key carefully to assess your results. Your Benchmark Quiz analysis will help you determine how much time you need to spend on the specific areas of percent in which you need the most careful review and practice. 

To change a fraction to a percent, first change the fraction to a decimal and then multiply it by 100. If the number is already presented as a decimal, directly multiply by 100. 

In addition, the website www.math.com has helpful mini lessons and further practice problems. Click on Percents under Hot Subjects. Then click on numbers under the word percent. Follow along with the lesson explanation and then practice problems. To explore the part/whole relationship of percents and how they are related to decimals and fractions, try http //matti.usu.edu/nlvm/nav/index.html. Click on the Virtual Library. Then choose Numbers and Operations under the column 9-12. Scroll down, and then click on Percentages. 

Switching from fractions to decimals to percents and back again Investigating both the practical and impractical with percents Using percentages to your advantage — in your best interest... 

A decimal is a fraction and vice versa. To change a fraction to a percent, you first determine the decimal value and then fiddle with the decimal point. That s all there s to it — really. 

The middle step in changing a fraction to a percent is finding the decimal equivalent (or, in the case of a repeating decimal, the approximate). Table 6-1 shows you some fractions, their decimal value, and then the percent that you get by moving the decimal point two places to the right. 

To write a fraction as a percent, first write the fraction as a decimal by dividing the numerator by the denominator 47 4- 53 = 0.886792. . ., or 0.887 to the nearest thousandth. Now, write the decimal as a percent by moving the decimal point two places to the right and adding the percent symbol. 0.887 = 88.7%. For more on this concept, see Chapter 11. 

Now that we know how to write fractions and mixed numbers as decimals, and we know how to write decimals as percents, we can write fractions and mixed numbers as percents by putting the two steps together. Write a fraction as a decimal, and then turn that decimal into a percent. 

Just as we converted fractions and mixed numbers to percents by first converting them to decimals, and then converting the decimals to percents, we go in the opposite direction to convert percents to fractions and mixed numbers. Begin by writing the percent as a decimal, and then write the decimal as a fraction or mixed number. 

We learned how to compare fractions to fractions in Chapter 3, and we learned how to compare decimals to decimals in Chapter 7. Now, we ll compare fractions to decimals, decimals to percents, and percents to fractions. How By first converting any fractions or percents to decimals. It is easiest to compare a decimal to another decimal. 

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