PRAXIS II: MATH CONTENT

These are not official mathematics definitions.

 

Cardinal number

a count of how many  ( 4 ducks)

Ordinal number

position (2nd duck in the row)

Nominal number

Relative position such as a house number. Does not indicate number before it as does the ordinal number.  Also identifiers such as numbers on athletic jerseys.

Distributive property

Distributes multiplication over addition or subtraction.   

2( x+4) = 2x+8

Commutative property

A change in order does not affect the outcome.  Multiplication and addition, but not for subtraction or division.  A+B=B+A  and A*B=B*A

Associative Property

A change in grouping but not order. Addition and Multiplication but not division or subtraction.  A + (B+C) = (A+B)+C and A*(B*C)=(A*B)*C

Prime number

Only factors are 1 and itself    2 ,3 ,5, 7, 11, 13, etc

Composite number

Factors in addition to 1 and itself     4, 6, 8, 9 etc

GCF

Greatest Common Factor: Largest number that will divide into 2 or more numbers  Example: 4 is the GCF of 8 and 12

LCM

Least Common Multiple: Smallest number that 2 or more numbers will divide into.  Example:  24 is the LCM of 8 and 12.

Order of operations

Powers, multiplication and division, addition and subtraction unless otherwise indicated by parentheses.

Reciprocal

The product of a number and its reciprocal is 1.   The reciprocal of a/b is b/a.

Algorithm

A routine process used to obtain a result to a problem.

Pascal’s Triangle

A triangular array of numbers representing the coefficients of a binomial expansion.

Series

A list of numbers with a common definition. Example: the odd or even numbers, prime numbers, Fibonacci numbers.

Arithmetic Series

Not all series are arithmetic or geometric, but arithmetic and geometric are two common series of numbers.

 

An arithmetic series  is a series with a common difference between terms, e.g., 3, 7, 11, 15, 19,…    a1 is the first term ( 3), d is the difference between terms (4) and n is the number of the term (the fourth term: a4 is 15 in this case)

The general rule for finding a term is an = a1 + d(n-1). If we want the 10th term:  a10 = 3 + 4(9) thus a10 = 39 for this series of numbers.

Geometric Series

A geometric series is a series with a common factor between terms, e.g.,  3, 6, 12, 24, 48,… or  8, 4, 2, 1, ½, ¼, 1/8, …  Once again the first term is a1,   n is the number of the term, and r is the common factor between terms. In the first example, r = 2 and in the second example r = 1/2 .  The general rule for finding a term is  an = a1r(n-1)   For example from the first series a8= 3(2)7   thus the 8th term is 3(128) which equals 384.  

Sequence

The sum of a series.   Example: sum of the odd numbers 1 thru 7  is 16.

Perpendicular

Lines meeting to form right angles

Parallel

Coplanar lines which do not intersect. Planes that do not intersect

Transformations

Common transformations in Geometry are the Rotation (turn), Reflection (flip) (how it would appear in a mirror), and the Slide.

Common System of Measurement

Common units: inches, feet, yards, miles, pints, quarts, gallons, ounce, pound, ton, and degree Fahrenheit.  These used to be called the English System of Measurement.

Metric System of Measurement

Common units: meters, liters, grams, and degree Celsius. Used with common prefixes of milli, centi, kilo.

Mean

Most commonly used measure for average. Sum of terms divided by number of terms.  The value if all terms were the same.

Median

Less commonly used measure of average.  Middle term in a list of ordered terms. Example: Seven is the median of 1, 4, 7, 8, 9    

Mode

Least commonly used measure of average. Most frequently appearing item or number in a list of terms.  Example:  3 is the mode for 1,1,3,3,3,3,5,6,6,7,8,9,9

 

Weighted average

Mean calculated after some scores a given more value than others. Example: test grades may count for two grades.

 

Range

Highest score minus lowest score. Also can be defined as highest score minus lowest score plus one. The latter form is rare.

Additive Inverse

Number added to another number to get zero.  Example -3 and 3

Multiplicative identity

A number multiplied by something to make the result one. The product of a number and its reciprocal.  Example:  3 and 1/3

Scalene triangle

No sides the same length

Isosceles triangle

Two sides the same length

Equilateral triangle

Three sides the same length.  Also is equiangular.

Acute triangle

All angles are less than 90 degrees

Obtuse triangle

One angle is greater than 90 degrees

Right triangle

One angle is 90 degrees

Volumes

Cylinder or Prism:

V = Bh (B is area of the base and h is the height)  Example:  Rectangular Based Prism: V=lwh.  Triangular Based Prism: V=1/2(abh).  Cylinder: V=πr2h. 

Volumes

Cones and Pyramids

V = 1/3 Bh   (B is area of the base and h is the height)  Example:  Rectangular Based Pyramid: V=1/3 lwh.  Triangular Based Pyramid: V=1/3(1/2abh).    Cone: V=1/3(πr2h). 

Factor tree

Simple diagram of prime factors of a number.

Celsius to Fahrenheit

F = 9/5(C) + 32

Fahrenheit to Celsius

C = 5/9(F -32)

 

NOTE:  -40 degrees C is equal to -40 degrees F