Author: Kathy Halverson
Last saved by: MHE
Company: Halverson Household

Lesson 5-3

Example 1	Multiply Fractions
Find  ⋅ .  Write the product in simplest form.

Multiply the numerators. 
Multiply the denominators. 

 ⋅  = 		            
	=  or 	Simplify.  The GCF of 15 and 35 is 5.

Example 2	Multiply Negative Fractions
Find .  Write the product in simplest form.
 ⋅   = 	Divide 5 and 15 by their GCF, 5.
	         = 	Multiply the numerators and multiply the denominators.
	         = -		Simplify.

Example 3	Multiply Mixed Numbers
Find 2 ⋅ 1.  Write the product in simplest form.    Estimate 3 · 2 = 6
2 ⋅  1 =  ⋅ 		Rename 23/4as 11/4and rename 15/7as 12/7.
	     = 		Divide by the GCF, 4.
	     = 		Multiply.
	     =  or 4	Simplify.

Examle 4      Multiply Rational Numbers to Solve a Problem
HEIGHT     Jacob is 65 inches tall.  Kyle is 14/15as tall as Jacob.  Find Kyle’s height.
To find Kyle’s height multiply 65 by .

65 · =  · 		Rename 65 as 65/1.
	= ·  		Divide by the GCF, 5.
	= 		Multiply.
	= or 60		Simplify.  Kyle is 602/3inches tall.

Example 5	Multiply Algebraic Fractions
Find .  Write the product in simplest form.
 ⋅  = 		The GCF of m^2 and m is m.
	      = 			Simplify.

Real-World EXAMPLE
Example 6	Use Dimensional Analysis to Solve a Problem
VACATION   The Green Family is driving to reach a vacation destination at a rate of 64 miles per hour.  How far does the Green Family travel in  hour?
		d =  ⋅  hour			distance = rate · time

Divide by the common factors and units. 

   = 				
		   = 48 miles				Simplify.

The Green Family travels 48 miles in  hour.