Developmental Math II
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Transcript of Developmental Math II
Developmental Math II
Al Grocia
Chapter 1
Module 0 – Numeric and variable expressions
NUMERIC EXPRESSIONS
numbers
• What is a number?
• What does a number “do”?
• What can we “do” with numbers?
• How many numbers are there here? 5 – 12
Building numbers – Operators
Geometric view• Adding -Line segments • Multiplying – rectangles
Algebraic view: abstract• Algebra defines 2 operators Add – combine terms Multiply – combine factors• with 9 properties Identity InverseCommutative Associative Distributive
Algebra meets geometry
Number lines and algebra tiles
Examples: 4 + 2 : 8 – 3 : 5(6) : 15÷3
geometric algebraic
Number lines/tiles
Examples:7 – 12 : -3 + -8 : (-3)(2) : (-6)÷(-2)
geometric• ?????
algebraic
Number lines/tiles
Examples
geometric algebraic
Number lines/tiles
Basic operations • Adding properties: order does not matter but signs do 0 is called the additive identity and does not change the value of a number when added to it opposites are numbers with the same units but different signs and opposites add to zero – these numbers are sometimes called additive inverses (discuss opposites vs subtraction vs negatives)• Multiplication properties Always use / for division sign and write division with fraction notation so that order doesn’t matter but numerator vs denominator does 1 is called the multiplicative identity and does not change the value of a number when multiplied by it Reciprocals are numbers with the numerator and denominator switched (flipped) and these numbers multiply to one – these numbers are sometimes called multiplicative inverses • Math “bee”
Exponent notation
• Actually not an operator in algebra – exponent notation is a functional notation for repeated multiplication-
• Exponent – a physically small number written to the right and raised higher than its base – the exponent counts the factors of a multiplication problem (or follows the ^ sign)
• Base – the repeated factor • Power – the answer to the problem
Prime factorization
• It is sometimes useful to view a number “unsimplified”
• You can break a number into terms or factors• For now we will explore factoring
vocabulary
• Integral factor – an integer (not a fraction/decimal) which is a factor of the given number (ie: divides exactly into it)
• Prime – a number that has exactly 2 integral factors
• Composite – a number that has more than 2 integral factors
• NOTE: 0 and 1 are neither prime nor composite • Note: 2 is the only even prime number
factoring
• Writing a number as the product of 2 or more other numbers is called factoring
ex: 56 = 8(7) 56 = (-2)(-28) 56 = (.5)(112)• Writing a number as the product of prime
numbers is called prime factoring 56 = 2(2)(2)(7) = 23 • 7
Tools for finding prime factoring• Hints: Be familiar with prime numbers : {2, 3, 5, 7, 11, 13…} Know some division tricks : Even numbers- divisible by 2 Ends in 0 or 5 – divisible by 5 Digits add up to 3 or 9 – divisible by 3 • Factor tree
• Factor tower
Building numbers with 2 or more operators
• Order of operations (pemdas - gema)• Multiplication first – combine factors - product
• Addition last – combine terms – sum • Ex:
Grouping symbols• Parenthesis, brackets, braces, radical signs, fraction bar, absolute value
bars…• Brackets and braces were used to make grouping in long nested problems
easier to track. They are seldom used any more therefore parenthesis must be “tracked”
ex: 4 – ( 9 – (8 + 3(-7) – 12)) + 15• Fraction bar is a division sign that groups the numerator and denominator ex: 6 + 21/3 • Absolute value bars: a grouping symbol that is also a function – | #### | - it
means “distance” and therefore turns the number inside to a positive value. ex: |2 – 8| |8 – 2|
Examples
Fractions
• Geometric view:
Fractions
• Algebraic view:
Fraction - summary• Multiplying and dividing fractions: reciprocals cancel, order doesn’t matter,
denominators do NOT need to match showing work: 1. factor numerator and denominator 2. rearrange order to show factors of 1 3. remove factors of 1• Adding and subtracting fractions: the addition must be grouped by using
COMMON DENOMINATORS and changing the division expression showing work: 1. show inserted factor that make the denominators the same 2. show regrouping 3. show added value 4. simplify if necessary – show factor of one that is removed
VARIABLE EXPRESSIONS
Variable – a number that changes value
• Variables have several uses 1. a blank to fill in with a given number 2. a way to maneuver an unknown number 3. a way to explore how one number affects other number
• a variable is used whenever the value of a number is unknown, unimportant, or unnecessary to answering a question
Evaluating variables
Chapter 2
Module 1 – linear equations, inequalities, functions
VARIABLE EQUATIONSSingle variable
INEQUALITIES AND NUMBER LINE GRAPHS
Single variable
VARIABLE EQUATIONSTwo or more variables