Transcript Properties of Real Numbers

Properties of Real
Numbers
Properties of Addition & Multiplication:
For all real #’s, a, b, c…
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Closure: then a+b is a real number
ab is a real number
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Commutative: a + b = b + a
ab = ba
Associative: (a+b)+c = a+(b+c)
(ab)c = a(bc)
Identity: a + 0 = 0 + a = a
a*1 = 1*a = a
1
Inverse: a + (-a) = 0
a 1
a
Distributive Property
For all real numbers a, b, and c:
a(b + c) = ab + ac and (b + c)a = ba + bc)
State a property to justify the
following statements…
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6 +(-3) = (-3) + 6
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3(4a+5) = 12a + 15
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(x+3) + 6 = 6 + (x+ 3)
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-5 + 5 = 0
State a property to justify the
following statements…
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2(4 – 5) = (4- 5)2
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-5 + (x + 2) = (-5 + x) + 2
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4 ( 1) = 4
Using Properties for Mental
Math
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A movie ticket costs $7.75. A drink costs
$2.40 and popcorn is $1.25. What is the
total cost?
Using Properties for Mental
Math
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You buy a sandwich for $2.95, an apple
for $.45, and a bottle of juice for $1.05.
What is the total cost?
Simplify – using properties
Simplify – using properties
Simplify – using properties
Simplify – using properties
Simplify – using properties
Simplify – using properties
Homework
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Worksheet