**Unit 3: Fractions**__A simple way to look at how to check for__

**Equivalent Fractions**

**equivalent fractions**is to do what is called “

**cross**-

**multiply**”, which means multiple the numerator of one

**fraction**by the denominator of the other

**fraction**. Then do the same thing in reverse. Now compare the two answers to see if they are equal.

**Adding and Subtracting Fractions**

In order to add or subtract fractions, YOU MUST HAVE A COMMON DENOMINATOR.

In order to determine a common denominator, you will have to find the LCM (unit 1!) of the denominators of the fractions you are working with.

Once you have identified a common denominator, you adjust the fractions in the equation by multiplying the numerator (top number) and denominator (bottom number) by the same factor or number. You will know which number to multiply the top and bottom by when you determine what number you can multiply the denominator by to create the common denominator.

**Videos:**Interactive Slides for Adding and Subtracting Fractions

Adding and Subtracting Fractions

## Adding & Subtracting Fractions and Mixed Numbers involve the same steps, however you must turn mixed numbers into improper fractions before you add or subtract.

**Converting Mixed Numbers and Improper Fractions**

To convert a mixed number to an improper fraction you must..

(1) Multiply the denominator by the whole number

(2) Add your product to the numerator

(3) Write your sum as the new numerator

(4) The denominator stays the same

To convert an improper fraction to a mixed number you must...

(1) Divide the numerator by the denominator

(2) The quotient is the whole number

(3) The remainder is the numerator

(4) The denominator stays the same

(5) Simplify the fraction if possible

**Converting Mixed Numbers and Improper Fractions**To convert a mixed number to an improper fraction you must..

(1) Multiply the denominator by the whole number

(2) Add your product to the numerator

(3) Write your sum as the new numerator

(4) The denominator stays the same

To convert an improper fraction to a mixed number you must...

(1) Divide the numerator by the denominator

(2) The quotient is the whole number

(3) The remainder is the numerator

(4) The denominator stays the same

(5) Simplify the fraction if possible

**Multiplying Fractions**- First, change any mixed numbers in the equation into an improper fraction

- Next, multiply numerator by numerator

- Then, multiply denominator by denominator.

- If your answer is an improper fraction, change it back to a mixed number.

- Check that your answer is in simplest form.

- Key words to check for in a word problem for multiplying fractions: OF, AS MANY AS

If you want more help, try watching this video:

**Multiplying Fractions**.

**Dividing Fractions**IF there is a mixed number in the equation you must FIRST turn it into an improper fraction.

Step 1. KEEP CHANGE FLIP: You must keep the first fraction, change the operation to multiplication and turn the second fraction

*(the one you want to divide by)*upside down (this is now a

**reciprocal**).

Step 2. Multiply the first fraction by that reciprocal

Step 3. Simplify the fraction (if needed)

**Video: How to divide a fraction by a whole number**

**Slides: Dividing Fractions**