Negative representations: (discuss historic and present international)
Integers: set of numbers: {..,-3,-2,-1,0,1,2,3,..}
Positive Integers, Zero, Negative Integers (Set View via models or
Measurement view via the number line); concept of negative being opposite
of
positive across pivot point at Zero)
8.1 Addition & Subtraction:
Set Model: Cancel effect: 4 positives + 3 negatives [i.e. 3 (-) cancels 3 (+) leaving 1 (+)]
Number
Line Model: a positives + b negatives:
move from
Zero
a units right and then b units left from new position
Addition
Properties: (if a, b, c are integers)
Closure: a + b is an integer | Cumutative:
a + b = b + a |
Associative:
(a + b) + c = a + (b + c) |
Additive
Inverse:
a + (-a) = 0 |
Identity
:
a + 0 = a = 0 + a for all a |
Theorem
- Additive Cancellation for Integers:
If a + c = b + c, then a = b |
Theorem
- Inverse of opposite:
- ( - a ) = a |
8.2 Multiplication, Division, and Ordering Integers:
If a and
b are integers:
1.
2.
3.
Multiplication
Properties: (if a, b, c are integers)
Closure: ab is an integer | Cumutative:
a x b = b x a |
Associative:
(ab)c = a(bc) |
Identity:
a x 1 = a |
Distribution:
(Multipilcation over addition):
a( b + c ) = ab + ac |
Multiplication
Cancellation:
Ac = bc, then a = b |
Zero Divisors:
ab = 0, iff a = 0 or b = 0 or both = 0 |
Theorem
- Multiplication by -1:
a (-1) = - a |
Theorem
- Multiplication of (-):
Case 1: (-a)b = -(ab) Case 2: (-a)(-b) = ab
|
Scientific Notation: An exponential representation of numbers in the form:
Where a is called the mantissa and n the characteristic of exponent
Ordering
Integers Properties: (if a, b, c are integers)
Transitive
Properties:
If a < b and b < c, then a < c |
<
addition:
If a < b, then a + c < b + c |
< Multiplication
by (+):
If a < b, then ac < bc |
< Multiplication
by (-):
If a < b, then a(-c) > a(-c) |
Use number line to order integers