Let’s talk about simplifying
fractions. To do that, we’re gonna talk about three
parts. One, what does it mean to simplify a
fraction? Two, why we would do it? And three, how would we simplify a
Number one, what does simplifying
fractions mean? To simplify a fraction is to make it as
simple as possible. You might also hear people use the word
reduce. Reducing fractions and simplifying
fractions are the same thing. Onto question two, why would we simplify
a fraction? We simplify a fraction for two main
reasons; it clarifies communication and it helps us avoid misunderstandings.
You might be wondering, what in the world
does she mean, clarify communication? Isn’t this math? And yes, I am talking about communication
in math because good mathematicians communicate clearly. Good mathematicians explain and present
their data in simplified terms. Here’s an example in clarity. Sara and Sam both took a math test and
their teacher gave them the grades you see on the screen. She gave Sara a 130 out of 182 and Sam
got 90 out of 126.
Whose score is higher? Did they do okay? Is this a good score for a math test? It’s not really clear. The simplified form of both of these
fractions is five-sevenths. Sam and Sara actually got the same
score. But it wasn’t clear because they were
using very complex fractions, instead of simplifying them. Taking the time to simplify fractions
makes your communication more clear and avoids misunderstandings between you and the people
you’re communicating your math to.
There is a third and more practical
reason, and that would be easier computations. For example, 130 over 182 𝑥 equals five
doesn’t seem like that simple of a problem to solve. But five-sevenths 𝑥 equals five is a
much easier problem to solve. Before we get to our third
how-to-simplify-fractions portion, there’s one more thing we need to note.
Simplifying does not change the value of
a fraction. It does not change how much we’re talking
about. Here is an illustration of the fact that
the value doesn’t change. The first pizza is four-eighths. The second pizza is two-fourths of a
pizza. The third pizza is one-half. Here, the only thing changing is the
number of slices but not the amount of pizza that you ate. One-half is four-eighths in a simplified
form. And one-half is also the simplified form
Now, on to how we simplify fractions. Let’s take the example four-eighths from
the pizza problem I just showed you and try and simplify it. To do that, I’m going to consider a
number that’s a factor of both the numerator and the denominator. In other words, I’m looking for a number
that the top and the bottom are both divisible by. So, in this problem, I recognize that
both the numerator and the denominator are divisible by four.
Now, I just divide the numerator by four
and the denominator by four, one-half. This was a very simple example and
probably one you can recognize immediately. You might even memorize that four-eighths
equals one-half. Not all fractions are that easy to
simplify. Here’s a slightly harder one.
Let’s simplify 12 over 28.
Again, we need to consider a number that
both 12 and 28 are divisible by. I’m going to start with four. The simplified form of 12 over 28 is
Here’s another example to simplify, 30
Our process is still the same. We need to come up with a number that 30
and 72 are both divisible by. I recognize that 30 and 72 are both even
numbers, so I’m going to start there and divide them both by two. This gives me 15 over 36. 15 over 36, however, is not the simplest
form of this fraction. If you look closely, there’s a number
that 15 and 36 are both divisible by, and that number is three. When I divide the top and bottom by
three, I get five twelfths. And I know that five twelfths is the
simplest form of this fraction because five and 12 do not share any common factors. Here’s our final example.
Adults need eight hours of sleep per
day. What fraction of the day is this? Give your answer in simplest form.
We can identify that in our problem, we
have these two pieces of information, eight hours of sleep is what they need per day. We also know that that means 24
hours. So, we can start with our fraction of
eight twenty-fourths. We then need to reduce the fraction just
like all the others we’ve practiced. Eight and 24 share a common factor of
eight, so we’re gonna divide the numerator and the denominator by eight here. When you divide the numerator and the
denominator by eight, you get the simplified fraction one-third. Based on the information given, that
would mean that adults need to sleep one-third of the day.
Simplifying fractions is a simple process
that helps us communicate effectively. And now, you have the tools to simplify
fractions and communicate more clearly to the people around you.