Lesson on Multiplying and Dividing Fractions

Multiplying Fractions

This is the easy one. If fact, you've already done it when you were adding fractions and finding a common denominator.

When multiplying fractions, just multiply straight across. Numerator times numerator. Denominator times denominator. That's it.

Multiple Choice

What's the rule for multiplying fractions?

• Just multiply straight across.

• Keep, Change, Flip

• You must have a common denominator

Multiple Choice

Find the product. 

• 2/14

• 1/49

• 2/7

• 1/14

Multiple Choice

Find the product.

• 9/24

• 9/28

• 6/32

• 1/28

Multiple Choice

  $$\frac{1}{2}\times\frac{4}{5}$$

Multiply the following equation:

• $$\frac{4}{10}$$  

• $$\frac{5}{7}$$  

Multiple Choice

Find the product.

• 3/50

• 30/5

• 6

• 1  1/5

Multiple Choice

$$\frac{1}{2}\ \div\ \frac{3}{5}\ =$$   Multiply and write in simplest form. 

• $$\frac{5}{6}$$  

• $$\frac{-5}{6}$$  

• $$\frac{3}{10}$$  

• $$\frac{-3}{10}$$  

Poll

How do you feel about multiplying fractions?

• Great (it's pretty easy)

• Horrible (I'm so lost)

• Eh... it's okay.

Dividing Fractions

Rule#1 for Dividing Fractions: DON'T DIVIDE.

Instead of dividing you do this procedure:

KEEP, CHANGE, FLIP

Dividing Fractions

Multiple Choice

After I "Keep, Change, Flip" what equation would I have? $$\frac{1}{2}\div\frac{2}{5}$$  

• $$\frac{2}{1}\times\frac{2}{5}$$  

• $$\frac{1}{2}\times\frac{5}{2}$$  

Multiple Choice

Solve $$\frac{1}{2}\div\frac{2}{5}$$  

• $$\frac{4}{5}$$  

• $$\frac{5}{4}$$  

• $$\frac{2}{10}$$  

Multiple Choice

Solve:

$$\frac{1}{10}\div\frac{2}{3}$$  

• $$\frac{3}{20}$$  

• $$\frac{2}{30}$$  

Multiple Choice

Solve

$$\frac{3}{4}\div\frac{1}{2}$$  

• $$\frac{5}{4}$$  

• $$\frac{3}{8}$$  

• $$\frac{6}{4}$$  

Multiple Choice

Solve:

• -9/10

• 10/9

• 9/10

• 6/8

Multiple Choice

• $$\frac{6}{40}$$

• $$\frac{3}{4}$$

• $$\frac{1}{2}$$

• $$\frac{12}{20}$$

Poll

How do you feel about dividing fractions?

• Great (it's pretty easy)

• Horrible (I'm so lost)

• Eh... it's okay.