3 - DECIMALS AND PERCENTS

Abstract

This chapter focuses on decimals and percents. Decimals and percents are forms of fractions and are often more convenient than the usual fractions. A decimal system is based on tens. The American money system is an example of a decimal system. Numbers, such as 0.3, 0.25, and 0.476 are called decimal fractions. A decimal fraction is a proper fraction whose denominator is a power of ten. Usually, the denominator is not expressed. If a number is written as a whole number, plus a decimal fraction, it is called a decimal number or a decimal. The decimal point separates the whole number and the fraction. The chapter discusses addition, subtraction, multiplication, and division of decimals. Percents are common because they are a convenient way of expressing a ratio. Percent means the number of parts per hundred. To write a decimal as a percent, multiply it by 100, moving the decimal point two places to the right. To write a fraction as a percent, multiply it by 100 and simplify.