Algebra 1 - Chp 1 - Numbers & Variables

number line

numbers can be placed in correspondence with points on a line

origin

the point corresponds to the number zero; the place where something begins

positive number

a number that corresponds to a point on th episitive side of a number line

negative number

a number that corresponds to a point on the negative side of the number line

graph on the number

on a number line the point that correspoinds to a number

real number

any number that is either a positive number, a negative number or zero

directed numbers

positive and negative numbers suggest opposite directions

equal set

sets that contain exactly the same members

one-to-one correspondence

Although the set are not equal, there is an important relations between them

roster

list all the members of a set

rule

specify a set by writing within the braces a description that identifies the members of the set; example: {1, 3, 5, 7,} = {the odd numbers between 0 and 8}

graph of set

graph the numbers on a line; set of points corresponding to a set of numbers

subset

if every member of a set S is also a member of set T, then S is a subset of T; symbol C;

empty set or null set

set contains no members

Venn diagram

diagram showing how certain sets are related

natural numbers or counting numbers

set of numbers used in counting; symbol N

whole numbers

expand the set of natural numbers to include the number 0; symbol W

integers

All whole numbers (both positive and negative) and zero; pattern continues without end in both directions; symbol J

rational numbers

any number that can be expressed as the quotient of tow integers, provided the divisor is not 0; exxample: 0= 0/1, 7=7/1, .21=21/100; symbol Q

irrational numbers

numbers that cannot be expressed as the quotient of two integers; symbols R

infinite set

each of the sets N (Natural numbers), W (Whole numbers), J (integers), Q (Rational Numbers ), R (Irrational numbers)

finite set

a set that is not ian nfinite set

numerical expression or numeral

a name for a number; example: 4 x 9 = 36

simplify the expression

a numerical expression with the simplest or most common name; example: 36 vs. 4 x 9 -=36

substitution principle

changing the numeral by which a number is named in an expression does not change the value of the expression

variable

symbol used to represent one or more numbers

domain or replacement set

set of numbers that a variable may represent

value of the variable

each number in the domain

variable expression

contains one or more variables and also may contain other symbols

evaluate the expression or find the value of the expression

when you replace each variable in a variable expression with one of its values and simplify the resulting numerical expression

mathematical expression

a numerical express or a variable expression

grouping symbol

is a device, such as a pair of parentheses, that is used to enclose an expression; braches, [ ] or braces { }

base

in an expression like 3 x 3 x 3 x 3 x 3 = 3 to the 5th power; the base is 3

exponent

in a power, the number of times the base occurs as a factor; example: 3 x 3 x 3 x 3 x 3 = 3 to the 5th power; the exponent is 5

exponential form

3 to the fifth power is noted as expontential form

order of operations

1. first simplify expressions within grouping symbols
2. then simplify powers
3. then, simplify products and quotients in order form left to right
4. then simplify sums and differences in order from left to right

mathematical sentence

a statement that indicates a relationship between two mathematcial expressions

equation

if a mathematical sentence states that two expressions name the same number; the equal sign, =

sides of equation

two expressions; example; 4 x 7 = 28; 4 x 7 is the left side of the equation and 28 is the right side

sides of the inequality

the expressions to the left and right of an inequality symbol

open mathematical sentence or open sentence

a mathematical sentence that contains at least one variable; example: 2x - 5 = 35

solution or root

any value of the variables for which the open sentence is true

solution set

the set of all solutions of the system

satisfy

each member of the solution set of an open sentence is said to satisfy the open sentence

graph of an open sentence

is the graph of its solution set

set-builder notation

the set of all "x" such that "x" is greater than 1