What I Have Learned About Grade 9 Fractions -Updated Version

What is a Rational Number?

A rational number is any number that can be written as a fraction or a quotient. Example: $\frac{1}{2}$ = A rational number

What I know about Number Lines

You can place fractions on a number line between whole numbers. In order to do this you have to make them have a common denominator. For example you can place $8\frac{2}{3}$ and $8\frac{5}{6}$ between the numbers 8 and 9 on the number line. But before you can do that you have to find a common denominator, which would change them to $8\frac{4}{6}$ and $8\frac{5}{6}$ . You can then plot them on the number line.

What I know about Comparing Fractions

How can you tell if a rational number is greater than another? You can create a common denominator to find out which one is greater than the other.
For example: Which fraction is greater? $\frac{1}{3}$ or $\frac{2}{4}$
Find the common denominator and change it to $\frac{4}{12}$ and $\frac{6}{12}$
Now you can see that $\frac{6}{12}$ is greater than $\frac{4}{12}$ because 6 parts out of 12 is greater than 4 parts out of 12.

What I know about Adding and Subtraction Fractions

For both adding and subtracting fractions you have to find a common denominator
For example: $\frac{-2}{3}$ + $\frac{1}{5}$ you would need to change it to $\frac{-10}{15}$ + $\frac{3}{15}$
Next, you would add the numerators and keep the denominator the same which would equal to $\frac{-7}{15}$
The same rules apply for subtracting fractions

What I know about Multiplying Fractions

You don’t need a common denominator when multiplying fractions. Like Ms. Burton says it’s a “Just do it question.”
For example: $\frac{2}{3}\times\frac{1}{5}$ is equal to $\frac{2}{15}$
If your answer is a fraction that is not in its’ simplest form, you would simplify it.
To simplify a fraction you would divide both the top and bottom of the fraction by the greatest common factor. For example in $\frac{8}{12}$ the largest number that would go exactly into both 8 and 12 would be the number 4. You would divide both the top and bottom by 4 and you would get the simplified fraction of $\frac{2}{3}$

What I know about Dividing Fractions

Let’s look at the equation $\frac{1}{2}\div\frac{1}{6}$
You would need to change the second fraction in the division equation upside down. It becomes a reciprocal. For example $\frac{1}{6}$ would become $\frac{6}{1}$
Next you would change it from a division question to a multiplication question $\frac{1}{2}\times\frac{6}{1}$ = $\frac{6}{2}$ = 3

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