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In the last exercise, we pointed out that using return makes programs more maintainable and flexible, but how exactly?

When functions return their value, we can use them together and inside one another. If our calculator needed to have a Celsius to Fahrenheit operation, we could write it with two functions like so:

function multiplyByNineFifths(celsius) { return celsius * (9/5); } function getFahrenheit(celsius) { return multiplyByNineFifths(celsius) + 32; } console.log('The temperature is ' + getFahrenheit(15) + '°F'); // Output: The temperature is 59°F

Take a look at the getFahrenheit function. Inside of its block, we called multiplyByNineFifths and passed it the degrees in celsius. The multiplyByNineFifths function multiplied the celsius by (9/5). Then it returned its value so the getFahrenheit function could continue on to add 32 to it.

Finally, on the last line, we interpolated the function call within a console.log statement. This works because getFahrenheit returns it's value.

We can use functions to section off small bits of logic or tasks, then use them when we need to. Writing functions can help take large and difficult problems and break them into small and manageable problems.

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