Pam's Scribe Post

integers lesson

 

When multiplying integers, here is the basic lesson.
Here's an example:
(+7) x (+2)=
In words, this would be seven groups of positive 2.
In repeated addition: (+2) + (+2) + (+2) + (+2) + (+2) + (+2) + (+2) =
You could use integer chips as so:

The red symbolizes positive.

You can also represent this equation as a number line, either vertical or horizontal.

And you'll have your answer, which is (+14).

Here's something new:

scribe rule

 

When the integers have the same value (+ or -), the product is positive.

When the integers have different values (+, - ), the product is negative.

 

Let's apply this rule.

(+5) x (+4) =

Just multiply and then see whether or not the signs match or not.

5x4= 20

both positive, so the answer is positive.

(+ 5) x (+4) = +20)

 

(-6) x (+2)=

Multiply, 6x2= 12

They have different signs, meaning it's negative.

 

(-7) x (-8)=

Find the answer of 7x8, = 56

Then to see whether 56 or the answer is positive or negative, check the signs.

The two signs are the same, meaning the answer is going to be positive.

= (+56)

 

sign rule part 2

 

When multiplying integers , count the negative signs. When the number turns out to be an even number, it is going to be a positive product, and an odd number while counting equals to a negative product.

 

For example: (+4) x (+6) x (-7) x (-1) =

count the negative signs, and there are 2.

2 is an even number, therefor the answer will turn out to be a positive product.

 

To solve it, just do order of operations.

 

(+4) x (+6) x (-7) x (--1) =

(+24) x (-7) x (-1) =





(-168) x (-1)=
(+168) = answer. :)
See, it's a positive product.

Let's try this again.
(-4) x (-1) x (-3) x (+2) =
by following the same rule from before, this must be a negative product since there are 3 negative signs, and 3 is odd.

(-4) x (-1) x (-3) x (+2) =
(+4) x (-3) x (+2) =
(-12) x (+2)=
(-24) = answer
                                       
Let's try with more factors.
(-4) x (+2) x (-1) x (+1) x (-5) x (+1) =
There are 3 negatives, and 3 is an odd number meaning that the answer is going to be a negative product.

(-4) x (+2) x (-1) x (+1) x (-5) x (+1) =
(-8) x (-1) x (+1) x (-5) x (+1) =
(+8) x (+1) x (-5) x (+1) =
(+8) x (-5) x (+1) =
(-40) x (+1) =
(-40)= answer.
See it wasn't that bad.
If you're having problems with multiplying integers, please refer to the video below,




















P
Please feel free to play this game, and apply the sign rules to your answers. :)


Integer Multiplication Game

Have fun, and Good Luck! :)