Section 21.4 Closing Ideas
For the overwhelming majority of real life situations (especially work situations) that you can imagine, if there are any parts of a whole involved, it will probably be done with decimals. And in most of those real life situations, if you need to do a calculation, you would do it with a calculator. So why do we need to learn how to do these basic calculations, and what is the value of relating things back to fractions?
Remember that the ability to calculate a number and the ability to understand that number are two separate skills. If you type in some calculations and get 5.07 and 5.1 as the results, you may still need to decide which of those is greater. You might be surprised (or maybe not) that a fair number of adults will get that comparison wrong. Part of this is simply on the level of numerical and computational literacy, which is to help you correctly understand and use information in the real world.
The importance of being able to work with fractions is that there's a lot of information that is better communicated and more accurately communicated using fractions than decimals. For example, there are situations where it's easier to think about getting 8 items for $3 than it is to think about getting each individual item for approximately $0.38 each. And that ratio is much more useful as the unreduced fraction \(\frac{\$ 3}{\text{8 items}}\) if you need to buy in increments of 8 (like hot dog buns).
The value is not only in having two different ways of thinking about it, but also being able to relate the two together. Sometimes fractions are the better tool and sometimes decimals are the better tool. And so it is beneficial to be able to take the information you have and apply the right tool to solve the problem instead of forcing yourself to use the wrong tool because you don't know how to use the other one. There's a well-known saying to this effect: "If all you have is a hammer, everything looks like a nail."