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Directed Numbers Math Review

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Directed numbers are just numbers with a positive or negative sign in front of them!

Directed numbers are signed numbers i.e. numbers with a positive or plus sign (+) in front of them or a negative or minus sign (-) in front of them  e.g.  +6, -2, +7 etc.  All these whole numbers (and 0) grouped together are called integers.

 

These numbers can be represented on a number line.

 

Number line

 

A positive number signifies a movement to the right.
A negative number signifies a movement to the left.

A number lacking a sign is positive.

Adding and Subtracting.

 e.g.  +2 + -3 + 2

Adding and subtracting positive and negative numbers

 

+2 + -3 + 2 = +1

 

Note:  A double negative changes to a single positive e.g.  +3 - -3 = +3 +3 = +6

A  negative sign with a positive sign changes to a single negative
e.g.  3 + -4 = 3 – 4 = -1
3 + -4 = 3 – 4 = -1

Multiplying and Dividing.

The following rules apply:

 

+ x + = +   +6 x +6 = +36
+ x - = -   +6 x -6 = -36
- x + = -   -6 x +6 = -36
- x - = +   -6 x -6 = +36

 

The same rules apply for division

Math problems for you to try.

Note:  Remember the correct order of operations.

  1. 8 - 11
  2. 5 - (-2)
  3. 9 - (6 - 9)
  4. -3 x -4
  5. -11 - (3 + 4)
  6. 3 x (-2)²

Solutions:  1)  -3    2)  +7    3)  +12    4)  +12    5)  -18    6)  +12