Decimals are important because people use them everyday in different situations, such as counting money, looking at price tags, reading an odometer and reviewing Olympic scores. The decimal system is a way to express large and small numbers by utilizing the decimal point.
Similarly, using the decimal system is less cumbersome than writing, adding, subtracting or multiplying mixed numbers with fractions. For example, it is easier to write ten and a half as 10.5 than as 10 1/2. Adding decimals like 10.5 and 29.75 is much easier than add 10 1/2 and 29 3/4, where you need to replace the fractions with common denominators before adding them. Likewise, it is easier to compare decimal numbers than fractions.
The decimal system, which uses base 10, is a system used for calculation in the sciences and engineering disciplines that can require more precision. Additionally, people need decimals in everyday life for the most basic of tasks.