MATH PRAXIS �REVIEW�
13
REAL NUMBERS
REAL NUMBERS
PRIME & COMPOSITE NUMBERS
ABSOLUTE VALUE
|4| = DEFINED AS ABSOLUTE VALUE OF 4
-4 AND 4 BOTH HAVE AN ABSOLUTE VALUE OF 4
EXPONENTIAL EXPRESSIONS
a3=a x a x a
4³= 4 X 4 X 4 = 64
PLACE VALUE� ANY NUMBER RAISED TO ZERO POWER EQUALS ONE: �30 = 1�SO … 5 ( 100 ) = 5 X 1 = 5
REMEMBER 10 RAISED TO 0 EQUALS ONE
POWER OF 10
| STANDARD FORM | FRACTIONAL FORM | PLACE VALUE |
10³
| 1,000 | 1,000 1 | THOUSAND |
10²
| 100 | 100 1 | HUNDREDS |
10¹
| 10 | 10 1 | TENS |
10°
| 1 | 1 1 | ONES |
10¯¹
| 0.1 | 1 10 | TENTHS |
10¯²
| 0.01 | 1 100 | HUNDREDTHS |
10¯³
| 0.001 | 1 1000 | THOUSANDTHS |
ORDER OF OPERATIONS
Please Excuse My Dear Aunt Sally
4(5-2)² - 2³ =
5 – 2 = 3
3 X 3 = 9
4 X 9 = 36
2 X 2 X 2 = 8
SO
36 – 8 = 28
SQUARES
4X4=16
5X5=25
6X6=36 ALSO 6²
CUBES
2X2X2=8
3X3X3=27 ALSO 3³
COMMON MATH SYMBOLS
COMMON MATH SYMBOLS
EXAMPLE
5 ≤ 7 – p
Which of the following is equivalent to the inequality above?
P ≤ 2
P ≥ 2
Since 7 subtract p is greater than or equal to 5 (≤), then 7 subtract ?
(what number) must equal a number equal to or greater than 5.
7 subtract 1 equals 6 (that works) 7 subtract 2 equals 5 (that works), 7 subtract 3 equals 4 (that doesn’t work). So the answer is P ≤ 2 (P is less than or equal to 2).
COMMUTATIVE LAW �OF �ADDITION & MULTIPLICATION
2 + 3 = 3 + 2 BOTH EQUAL 5
2 X 3 = 3 X 2 BOTH EQUAL 6
ASSOCIATE LAW�OF ADDITION AND MULTIPLICATION
(2 + 3) + 4 = 2 + (3 + 4) BOTH EQUAL 9
(2 X 3) X 4 = 2 X (3 X 4) BOTH EQUAL 24
IDENTITY ELEMENT �FOR ADDITION AND MULTIPLICATION
ANY NUMBER ADDED TO 0 GIVES THE ORIGINAL NUMBER.
4 + 0 = 4
ANY NUMBER MULTIPLIED BY 1 GIVES THE ORIGINAL NUMBER.
4 X 1 = 4
ADDITIVE INVERSE
3 + -3 = 0
RECIPROCAL
MULTIPLICATIVE INVERSE
DISTRIBUTIVE PROPERTY
2(3 + 4) = 2(3) + 2(4)= BOTH EQUAL 14
PLACE VALUE
5 EQUALS 5 ONES
4 EQUALS 4 GROUPS OF TEN
3 EQUALS 3 GROUPS OF HUNDRED
IN THIS EXAMPLE THE NUMERAL 3 IS MORE THAN THE NUMERAL 5 BECAUSE THE “5” MEANS 5 ONES, BUT THE “3” MEANS 3 HUNDREDS.
PLACE VALUE
PLACE VALUE
685,321
648,955
THE 8 IN THE TOP NUMBER REPRESENTS
HOW MANY TIMES WHAT THE 8
IN THE BOTTOM NUMBER REPRESENTS?
ANSWER
TEN TIMES
PLACE VALUE
WHICH NUMBER IS THE LEAST?
0.203
0.2041
0.20051
0.21
ANSWER
0.20051
EXPANDED NOTATION
ROUNDING OFF NUMBERS
345,723 ROUNDS TO 350,000
343,723 ROUNDS TO 340,000
3.4678 ROUNDS TO 3.47
3.4629 ROUNDS TO 3.46
ESTIMATING
Example: 34 X 987 (= 33,558)
ANSWER: ROUND 987 TO 1,000
34 x 1,000 = 34,000
ADDING/SUBTRACTING �WITH NEGATIVE NUMBERS
IF TWO LIKE SIGNS
(+) (+) THEN (+3) + (+2) = 5 or just 3 + 2 = 5
(-) (-) THEN (-14) - (-4) = -10 or just -14 + 4 = -10
(subtracting a negative number is similar to adding: 8 – (-3) = 8 + 3 = 11)
IF TWO UNLIKE SIGNS
(+) (-) THEN (+12) + (-4) = 8 or just 12 – 4 = 8
(adding a negative number is similar to subtraction: 8 + (-3) = 8 – 3 = 5)
(-) (+) THEN (-19) - (+6) = -25 or just -19 – 6 = -25
INTEGERS
MULTIPLYING AND DIVIDING�WITH NEGATIVE NUMBERS
| MULTIPLY | DIVIDE | |
SAME | -5 X -5 = 25 | -8 ÷ -4 = 2 | SAME |
DIFFERENT | -5 X 5 = -25 | -8 ÷ 4 = -2 | DIFFERENT |
SAME | 5 X 5 = 25 | 8 ÷ 4 = 2 | SAME |
DIFFERENT | 5 X -5 = -25 | 8 ÷ -4 = -2 | DIFFERENT |
FRACTIONS
13
FRACTIONS
CONVERTING FRACTIONS TO DECIMALS.
CONVERTING DECIMALS TO PERCENTS.
SIMPLY MOVE DECIMAL TWO PLACES OVER.
.60 EQUALS 60%
CONVERTING IMPROPER FRACTIONS TO PROPER FRACTIONS.
FACTORS
EXAMPLE
8 = 2 X 4 ALSO 8 = 1 X 8
THEREFORE
THE FACTORS OF 8 ARE 1,2,4,& 8
COMMON FACTORS
24: 1,2,3,4,6,8,12,24
36: 1,2,3,4,6,9,12,18,36
COMMON FACTORS ARE
1,2,3,4,6,& 12
GREATEST COMMON FACTOR
12: 1,2,3,4,6,12
30: 1,2,3,5,6,10,15,30
THEREFORE
1,2,3,& 6 ARE ALL THE COMMON FACTORS
BUT 6 (SIX) IS THE GREATEST COMMON FACTOR.
MULTIPLES
EXAMPLE
THE MULTIPLES OF 8 ARE 8,16,24,32,…
LEAST COMMON MULTIPLE
3: 3,6,9,12,15,18,21,24
4: 4,8,12,16,20,24,28
THE LEAST COMMON MULTIPLE OF THREE (3) AND FOUR (4) IS 12
ADDING�FRACTIONS
ADDING FRACTIONS
ADDING FRACTIONS
SUBTRACTING�FRACTIONS
SUBTRACTING FRACTIONS
SUBTRACTING FRACTIONS
MULTIPLYING FRACTIONS
DIVIDING FRACTIONS�TO DIVIDE A FRACTION YOU SIMPLY MULTIPLY THE NUMBER BY THE RECIPROCAL OF THE FRACTIONS.
ADDING�MIXED FRACTIONS EXAMPLE
SUBTRACTING �MIXED FRACTIONS EXAMPLE
MULTIPLYING �MIXED FRACTIONS
DIVIDING MIXED FRACTIONS
ADDING AND SUBTRACTING�DECIMALS
EXAMPLE
4.316 + 179.5 =
4.316
+ 179.5
183.816
MULTIPLYING DECINALS
25.35 (TWO DECIMAL PLACES)
X 0.12 (TWO DECIMAL PLACES)
5070
25350
3.0420 (TWO PLUS TWO EQUALS FOUR DECIMAL PLACES)
DIVIDING DECIMALS
.2 12.64�
2. 126.4
.
2 126.4
63.8
2 126.4
MAKE THE DIVISOR A WHOLE NUMBER BY MOVING THE DECIMAL POINT TO THE RIGHT. MOVE THE DECIMAL IN THE DIVIDEND AN EQUAL NUMBER OF SPACES.
PLACE THE DECIMAL POINT IN THE ANSWER LINED UP WITH THE DECIMAL POINT IN THE DIVIDEND
DIVIDE THE NUMBER MAKING SURE THE DECIMAL POINTS REMAIN LINED UP
HOW TO COMPARE AND ORDER FRACTIONS, SMALLEST TO LARGEST
FUNCTION RULES FOR DATA
A FUNCTION IS A RULE (AN EQUATION) THAT SHOWS A RELATIONSHIP BETWEEN AN INPUT AND THE OUTPUT
IT IS OFTEN
GIVEN AS A FORMULA
F(x) = 3x + 5
Meaning
TAKE AN INPUT
(FOR EXAMPLE … 7)
MULTIPLY IT (7) BY 3
AND ADD 5
EQUALS 26
FUNCTION RULES FOR DATA
CONSIDER THEN THAT IF YOU TAKE 60
AND APPLY THE FUNCTION RULE
AND YOU GET 24
SO WE KNOW THEN THAT . . .
60 x ? = 24
TO FIND THIS YOU SIMPLY DIVIDE 24 BY 60
YOU GET .4
SO
30 x .4 = 12
X | f (X) |
60 | 24 |
45 | 18 |
30 | ?? |
FUNCTION RULES FOR DATA
IN THIS CASE THE FUNCTION RULE
COULD BE Y = -X² - 2X
BECAUSE (SUBSTITUTING THE VARIABLES)
-(-1)² - 2(-1) = -1 + 2 = 1
X | Y |
-1 | 1 |
0 | 0 |
STATISTICAL QUESTIONS
IN ORDER FOR A MATH PROBLEM TO TYPICALLY BE CONSISDERED A STATISTICAL QUESTION, THE ANSWER MUST REQUIRE THE COLLECTING OF DATA AND WHERE THERE WILL ALSO BE A VARIABILITY OF DATA — THE PROBLEM CAN’T JUST BE ANSWERED BY COUNTING, FOR EXAMPLE.
RATIO
SOLVING RATIO PROPORTIONS
FINDING PERCENT
"this should be divided by 100“
2% = .02 and 20% = .2
1% = .01 and 10% = .1 and 100% = 1
WHAT IS 15% OF 60?
.15 X 60 = 9
70% OF WHAT NUMBER
IS 35?
70 35
----- = -----
100 X
CROSS MULTIPLY
100 X 35 ÷ 70 = 50
50 IS THE ANSWER
PERCENT CHANGE FORMULA
.2
5 1.0 or 20% decrease
PERCENT PROBLEMS
IF 5 PERCENT OF 300 STUDENTS HAVE PERFECT ATTENDANCE. WHICH EQUATION CAN BE USED TO DETERMINE THE NUMBER OF STUDENTS WITH A PERFECT ATTENDANCE RECORD?
1/4 X 300
1/20 X 300
1/5 X 300
5 X 300
ANSWER
1/20 X 300= 15 (15 STUDENTS)
FOR 1/20 EQUALS 5 PERCENT (1 DIVIDED BY 20 EQUALS .05, OR 5%)
. 05
20 1.00
CONVERTING A FRACTION TO A PERCENT
FINDING AVERAGES
MODE
THE MODE IS THE NUMBER THAT
APPEARS THE MOST OFTEN.
Example: 3,4,8,9,9,2,8,9
9 is the mode.
FINDING AVERAGES
MEDIAN
THE MEDIAN OF A SET OF NUMBERS
(ARRANGED IN ASCENDING ORDER)
IS THE MIDDLE NUMBER (if there is an
odd number of items in the set). If there is an even number in the set, the median is the mean of the middle two numbers.
Example: 3,4,6,9,21,24,56
9 is the median.
FINDING AVERAGES
THE MEAN IS WHAT IS USUALLY CALLED AVERAGE.
TO CALCULATE THE MEAN
ADD ALL OF THE NUMBERS.
THEN DIVIDE BY THE TOTAL NUMBER OF NUMBERS ADDED.
Example: 2,8,15,23
The mean is 48 ÷ 4 = 12
12 is the average.
FINDING RANGE
THE RANGE IS SIMPLY THE DIFFERENCE BETWEEN THE HIGHEST AND LOWEST NUMBERS IN A DISTRIBUTION.
FOR EXAMPLE
4,6,9,3,7
The lowest number is 3. The highest number is 9. The range is 9 – 3 = 6
So the range is 6 in this example.
AVERAGES
EXAMPLE
MEAN: 15
MEDIAN: 14
MODE: 13
RANGE: 8
PROBABILITY FORMULA
NUMBER OF FAVORABLE
OUTCOMES
PROBABILITY = -----------------------
NUMBER OF POSSIBLE
OUTCOMES
Example: Using the above spinner, what is the probability that you will spin a 6?
ANSWER 1 IN 8
WHEN TWO EVENTS ARE
INDEPENDENT OF ONE ANOTHER,
YOU HAVE TO MULTIPLY
Example: What is the probability of spinning a red and the number 2?
ANSWER: 1/4 X 1/8 = 1/32
COMBINATIONS
Example: How many combinations of shirts and ties are there if there are 5 different color shirts and 3 different color ties?
ANSWER: 5 X 3 = 15
SIMPLE PERMUTATIONS
Example: How many ways can you arrange the letters
L O V E in a row?
ANSWER: 4 X 3 X 2 X 1 = 24
Example: How many ways can you arrange 5 boxes of cereal in a row?
ANSWER: 5 X 4 X 3 X 2 X 1 = 120
TYPES OF POLYGONS
13
CONVEX & CONCAVE
CONVEX HEXAGON: Any 2 points
of this figure can be connected
with a straight line with all parts
of the line staying within the figure.
For a
CONCAVE HEXAGON
this is not true.
A POLYGON is a closed plane figure, having three or more, usually straight, sides; triangle, square, hexagon�An “irregular” polygon is one that does not have all sides equal and all angles equal.�A polygon is "regular" only if all angles are equal and all sides are equal otherwise it is irregular.�
TYPES OF�TRIANGLES
TYPES OF QUADRILATERALS
COORDINATE GEOMETRY
�GRAPHS�
TYPES OF ANGLES
13
�INTERSECTING LINES AND ANGLES MOVING ACROSS PARALLEL LINES�
========
ANGLES 1 & 2 EQUALS
180 DEGREES
ANGLES 1,2,3, & 4
EQUALS 360 DEGREES
ANGLES
AN ANGLE IS FORMED BY TWO RAYS THAT SHARE THE SAME END POINT (THE END POINT IS CALLED THE VERTEX).
ANGLES
ADJACENT ANGLES SHARE A COMMON SIDE AND A COMMON VERTEX. ANGLES 1 & 3 ARE ADJACENT ANGLES AS ARE ANGLES 2 & 4.
VERTICLE ANGLES ARE FOUND OPPOSITE ONE ANOTHER. ANGLES 1 & 4 ARE VERTICLE ANGLES AS ARE ANGLES 2 & 3.
SUPPLEMENTARY ANGLES HAVE A SUM OF 180 DEGREES (MAY FORM A STRAIGHT LINE). ANGLES 1 & 3 ARE SUPPLEMENTARY.
1
2
3
4
ANGLES
A RIGHT ANGLE HAS A MEASURE OF 90 DEGREES.
AN ACUTE ANGLE HAS A MEASURE LESS THAN 90 DEGREES.
AN OBTUSE ANGLE HAS A MEASURE OF MORE THAN 90 DEGREES.
RIGHT ACUTE OBTUSE
�PYTHAGOREAN THEOREM�
The Pythagorean Theorem is the relationship that exists among the three sides of a right triangle. It states that the square of the hypotenuse (the side opposite the right angle) is equal to the sum of the squares of the other two sides, i.e., A squared plus B squared equals C squared.
POLYGON�A TWO-DIMENSIONAL SHAPE WITH STRAIGHT SIDES: TRIANGLE, RECTANGLE, PENTAGON
REGULAR POLYGON
SIDES WITH THE SAME LENGTH
IRREGULAR POLYGON
SIDES OF DIFFERENT LENGTHS
RECTANGLE
7
3
RECTANGLE
AREA = LENGTH X WIDTH
PERIMETER = 2 X LENGTH + 2 X WIDTH
EXAMPLE
AREA = 21
PERIMETER = 20
TRIANGLE
3
8
3
CIRCLE
AREA = π X R² (pi X radius squared)
CIRCUMFERENCE = 2 X π X R
(2 X pi X radius)
EXAMPLE
AREA = 3.14 X 9 = 28.26
CIRCUMFERENCE = 2 X 3.14 X 3 = 18.84
RECTANGULAR SOLID
5
4
6
RECTANGULAR SOLID
SURFACE AREA EQUAL
2 X LENGTH X WIDTH + 2 X LENGTH X HEIGHT + 2 X WIDTH X HEIGHT
VOLUME EQUALS
LENGTH X WIDTH X HEIGHT
EXAMPLE
SURFACE AREA = 2(24) + 2(30) + 2(20)= 148
VOLUME = 5 X 6 X 4 = 120
CYLINDER
10
3
CYLINDER
SURFACE AREA = 2 X π (PI) X RADIUS X HEIGHT + 2 X π (PI) X RADIUS SQUARED
VOLUME = π (PI) X RADIUS SQUARED X HEIGHT
EXAMPLE
SURFACE AREA
(2 X 3.14 X 3 X 10) + (2 X 3.14 X 9) = 244.9
VOLUME
3.14 X 9 X 10 = 282.6
FLIP (also called reflection)…SLIDE (also called translation)…TURN (also called rotation)
SHAPES
SPHERE CONE TRIANGULAR PRISM CUBE CYLINDER
TRIANGULAR PYRAMID
�MEASUREMENT�
IS ABOUT 5 MILLILITERS
EQUAL 1 LITER
MEASUREMENT
FAHRENHEIT
CELSIUS
METRIC SYSTEM
KILO 1,000 | HECTO 100 | DEKA 10 | BASIC UNIT METER LITER GRAM | DECI 0.1 | CENTI 0.01 | MILLI 0.001 |
EXAMPLES
1 KILOMETER EQUALS 1,000 METERS
1 METER EQUALS 1,000 MILLIMETERS
1 LITER IS 1,000 MILLILITERS
1 KILOGRAM EQUALS 1,000 GRAMS
CONVERSION TO STANDARD
1 METER EQUALS 3.26 FEET
1 KILOMETER EQUALS 0.62 MILES
1 LITER EQUALS 0.26 GALLONS
1 KILOGRAM EQUALS 2.2 POUNDS
METRIC SYSTEM
A pencil is 15 centimeters long.
How long is the pencil in millimeters?
ANSWER
150
Why?
1 centimeter equals 10 millimeters.
ALGEBRA
PROBLEM
x + 6 = 10
SOLUTION
x + 6 – 6 = 10 – 6
x = 4
ALGEBRA
PROBLEM
x ÷ 3 = 4
SOLUTION
x ÷ 3 = 4
x ÷ 3 X 3 = 4 X 3
x = 12
ALGEBRA
PROBLEM
6y = 24
SOLUTION
6y = 24
6y ÷ 6 = 24 ÷ 6
y = 4
ALGEBRA
PROBLEM
8x + 3 = 27
SOLUTION
8x + 3 = 27
8x + 3 – 3 = 27 – 3
8x = 24
8x ÷ 8 = 24 ÷ 8
x = 3
ALGEBRA
BELOW THE EXPONENTS (ALSO CALLED THE DEGREES OF THE TERMS) ARE… 2 AND 3
THE COEFFICIENTS ARE … 6, 4, 7, AND - 5
6xy² - 4x + 7y³ - 5
TERMS
POLYNOMIALS
5xy² MONOMIAL (1 TERM)
5x - 2 BINOMIAL (2 TERMS)
4x + 5y² - 7 TRINOMIAL (3 TERMS)
ALGEBRA
MONOMIALS
DEGREE OF A MONOMIAL IS THE SUM OF THE EXPONENTS FOUND IN THE DIFFERENT VARIABLES INVOLVED.
A CONSTANT TERM HAS A DEGREE OF 0 (ZERO) UNLESS THE TERM IS 0 (THIS IS CONSIDERED AN UNDEFINED DEGREE).
THE NUMERIC CONSTANT IN A MONOMIAL IS CALLED THE COEFFICIENT.
BELOW IS THE DEGREE AND THE COEFFICIENT OF A FEW MONOMIALS.
MONOMIAL | 75 | 3x²y³ | -4x² | xy³ |
DEGREE | 0 | 5 | 2 | 3 |
COEFFICIENT | 75 | 3 | -4 | 1 |
ALGEBRAIC EXPRESSION AND EQUATIONS (difference between)
A MATHEMATICAL PHRASE GROUPING NUMBERS AND VARIABLES TOGETHER IS AN ALGEBRAIC EXPRESSION
7X + 4
AN ALGEBRAIC EQUATION IS A MATHEMATICAL PHRASE WITH
TWO EXPRESSIONS SET TO EQUAL ONE ANOTHER
7X + 4 = 50