unit 2.2  developing rules to multiply integers
what we need to know
 Multiplication is a form to shorten addition.
 Integers have the same properties as whole numbers.
 The multiplication of integers follow the rules of signs.
 Integers have the same properties as whole numbers.
 The multiplication of integers follow the rules of signs.
class notes
more information
the rule of signs
As we proved last lesson, the multiplication of integers follow the following rules:
Multiplication integer properties
A couple of things about the above properties:
 They also apply to NEGATIVE NUMBERS.
 Although it is a good idea to understand these properties, memorizing their names (if it is difficult for you) is not something you have to worry about. In other words, I expect you to understand the properties, but I will not ask you for their names.
ALSO, remember that:
 They also apply to NEGATIVE NUMBERS.
 Although it is a good idea to understand these properties, memorizing their names (if it is difficult for you) is not something you have to worry about. In other words, I expect you to understand the properties, but I will not ask you for their names.
ALSO, remember that:
(+4) x (+3). READS 3 groups of (+4)
(+4) x (3) READS 4 groups of (3)
(+4) x (3) READS 4 groups of (3)
rectangle model for multiplication of integers
One of the more effective means of finding products (multiplications) involves an AREA MODEL, which connects to the knowledge that the area of a rectangle is the PRODUCT of its width and length.
At our level, we should be able to realize that if we break the numbers down (the lengths), it'd make multiplication easier. For example:
This allows us to break the rectangle into 4 different multiplications:
So, the multiplication equals the SUM of all the 4 smaller multiplications:
600 + 90 + 140 + 21 = 851
600 + 90 + 140 + 21 = 851
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review  workbook
math_8__workbook__unit_2.2.pdf  
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