I understand how to divide fractions by other fractions but want to know why this is a useful mathematical technique. When do you need/want to divide a fraction by another fraction? What’s it useful for? Is it a specialist thing or am I missing an obvious application?
In: Mathematics
Division is useful anytime you need to know how many of one number makes up another number. And sometimes those numbers are fractions, which is when dividing fractions by other fractions would be necessary.
An example: let’s say you only have a half-teaspoon measure and you need to put 3 and a half teaspoons of salt in your recipe. How many scoops of salt would you need? Well… 3.5 = 7/2. So…
7/2 ÷ 1/2 = 14/2 = 7 scoops
As a side note, dividing fractions by other fractions is pretty much the same as multiplying them, which use useful to know because multiplying is usually easier. This is true because:
*a*/*b* ÷ *c*/*d* = *a*/*b* × *d*/*c*
(you just need to flip the divisor fraction)
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