Multiplying with Cross Cancelling

Multiplying Fractions

How do we do it?

First off it is much easier...

• Multiply tops

• Multiply bottoms

• Simplify

It looks easier right...

If you know your multiplication facts...

One more trick to make it easier...

Make sure you know how to cross cancel the fraction when multiplying

Let's do a quick review!

Do this kahoot...

Ok... first practice problem...

Do this multiplication

 $\frac{3}{4}\times\frac{1}{2}$  

Multiple Choice

What is 3 x 1?

• 3

• 4

• 2.65

• I don't know

Multiple Choice

What is 4 x 2?

• I dont' know

• 6

• 12

• 8

So now we have....

 $\frac{3}{8}$  

Can we simplify it?

Multiple Choice

Can we simplify 3/8?

• Yes

• No

• Maybe

• Not sure

Now for brute force repetition...

Multiple Choice

What is this...

$$\frac{3}{8}\cdot\frac{4}{6}=$$  

• $$\frac{3}{4}$$  

• 4

• $$\frac{1}{4}$$  

• 8

Multiple Choice

What is this...

$$\frac{3}{2}\cdot\frac{6}{2}=$$  

• $$\frac{9}{2}$$  

• 18

• 14

• $$\frac{1}{3}$$  

Multiple Choice

What is this...

$$\frac{5}{6}\cdot\frac{6}{5}=$$  

• 0

• 1

• 11

• I am confused

Poll

How do you feel?

• Great

• So so

• Not so good

• Completely confused