Sunday, October 26, 2014

Properties of Multiplication


Commutative Property:
The product doesn't change when you switch the order of the numbers being multiplied.

7 x 3 = 3 x 7

 x =


 x  



Zero Property:
Any number multiplied with a 0 equals 0.


24 x 0 = 0


 x 0 =








Identity Property:
Any number multiplied by 1 equals itself. 


2 x 1 = 2

  x 1 =  

1-2-3-Digit Multiplication

A digit is a number.  



is a single-digit number. 

9 x 9 = 81 
(single-digit multiplication)



is a two-digit number.

9 x 12 = 108
(1-digit x 2-digit multiplication)

12 x 12 = 144 
(2-digit x 2-digit multiplication)






is a three-digit number.

9 x 137 = 1,233
(1-digit x 3-digit multiplication)

12 x 137 = 1,644
(2-digit x 3-digit multiplication)


Estimating products



Estimating is when you solve multiplication problems by rounding the product to the greatest
place value.

Examples:

22 x 3 = ____ (estimate)

13 x  4 = _____(estimate)




Arrays and Equal Groups

An array is a group of objects organized into rows and columns.





Equal Groups can be used to show how multiplication works.

4 x 3 = 12 






Multiplication Riddle

Read and solve.


  1. I can be multiplied by 4 to make 32.  I can be made by multiplying 2 x 4.  What number am I? 
  2. If you multiply any of the numbers 1-9 by me, then you will get that number twice for an answer.  Multiply me by ten and you will get 110.  What number am I?

Multiplication Number Story


Read and solve.

1.  Cam Newton had 4 bags of footballs and each bag had 3 balls in it. How many footballs did Cam Newton have?



2.  Cam Newton threw 6 passes and made 4 yards each time. How many yards did he pass in total?








Multiples




Multiples are what you get after multiplying a number by an integer (not a fraction).



The following examples are multiples of 2:
0,2,4,6,8,10,12,14,16,18,20.......

this is because:
2 x 0 = 0
2 x 1 = 2
2 x 2 = 4 
2 x 3 = 6
(and so on)

The following examples are multiples of 5:
0,5,10,15,20,25,30,35,40.......

this is because:
5 x 0 = 0
5 x 1 =5
5 x 2 = 10
5 x 3 = 15
( and so on )

Extension facts




Extension facts are basic facts multiplied by a power of 10 (for example 10,100,1,000).

If 5 x 3 = 15,
then 50 x 3 = 150 and 500 x 3 = 1,500
and 5,000 x 3 = 15,000