Operations with Signed Numbers

 

 

Addition      Subtraction     Multiplication     Division

 

 

 

 
Addition Rules Examples
When adding two numbers with like signs, add the values and keep the common sign.

1. (+3) + (+5) = + 8

2.  4 +  6 = 10

3.  (-3) + (-5) = - 8

4.   - 4 + (- 6 ) = -10

When adding two numbers with unlike signs, subtract the values and use the sign of the larger-valued number. 

1. (+3) + (-5) = -2

2.  (-3) + (+5) = +2

3.   4 + (- 6 ) = -2

4.   - 4 + 6  = 2


Addition      Subtraction     Multiplication     Division

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Subtraction Rules Examples
Change the subtraction operator to addition and change the sign of the number that immediately follows. Follow the rules for addition stated above. 

(i.e. Add the opposite)

1. (+3) - (-5) = 

    (+3) + (+5) = 8

2.  (-3) - (+5) = 

     (-3) + (-5) = - 8

3.   4 - (- 6 ) = 

       4 + (+ 6 ) = 10

4.   - 4 - 6  = 

     - 4 + (- 6) = - 10


Addition      Subtraction     Multiplication     Division

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Multiplication Rules Examples
When multiplying two numbers with the same sign, the product is positive.

(+)(+) = +        (-)(-) = +

 

1. (+3) (+5) = +15

2.  (4)( 6) = 24

3.  (-3) + (-5) = +15

4.  - 4(- 6 ) = 24

When multiplying two numbers with unlike signs, the product is negative.

(+)(-) = -          (-)(+) = -

 

1. (+3) (-5) = -15

2.  4 (-6 ) = 24

3.  (-3)  (+5) = -15

4.  - 4 ( 6 ) = -24


Addition      Subtraction     Multiplication     Division

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Division Rules Examples
When dividing two numbers with the same sign, the quotient is positive.

(+)/(+) = +          (-)/(-) = +

 

1. (+3) (+5) = +15

2.  (4)( 6) = 24

3.  (-3) + (-5) = +15

4.  - 4(- 6 ) = 24

When dividing two numbers with unlike signs, the quotient is negative.

(+)/(-) = -          (-)/(+) = -

 

1. (+15) / (-5) = -3

2.  24 /(-6 ) = 4

3.  (-15) /(+3) = -5

4.  - 24 /( 6 ) = -4

Note: The division rules are the same as the multiplication rules.


Addition      Subtraction     Multiplication     Division

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