Transcript General School Presentation

Multiplying & Dividing Fractions
Multiplying Fractions
Multiplying fractions is easy.
Top x top = top
Bottom x bottom = bottom
1 3 1 3 3
 

2 4 24 8
Shoot straight!
Multiplying by a whole number
Make your whole number look like a fraction by
putting it over 1.
Top x top = top
Bottom x bottom = bottom
2 2 2 22 4
2   

5 1 5 1 5 5
Shoot straight!
Multiplying Mixed Numbers
Make your mixed numbers into improper fractions
first.
2 1 5 5 5  5 25
1
1 2   

or 4
3 2 3 2 3 2 6
6
Canceling
Canceling is a special tool reserved just for fractions
.
Any factor anywhere on the top can be canceled with
a matching factor on the bottom.
2 6 2 2  3 2
 
 2
3 2
1
32
The magic of “OF”
You can do many fraction problems in your head if
you can remember that ‘multiply’ can be replaced
by the word ‘of’ .
1
1
 8 is the same as of 8 or 4
2
2
Dividing Fractions
Dividing fractions is just doin’ the flip!
Flip the fraction after the
Multiply

3 1 3 2 3 2 6
1
   
 or 1
5 2 5 1 5 1 5
5
Remember:
Cancel if you can.
Multiply straight across.
Flip when you divide.
Change whole numbers or mixed number to
improper fractions.