# 8th-Semester1-Math-Vocabulary-Variables & Expressions, Real Numbers & the Number Line, Adding & Subtracting Real Numbers, Multiplying & Dividing Real Numbers, Evaluating Expressions & Combining Like Terms, Solving One-Step Equations, Solving Two-Step Equa

## 51 terms

### Numerical Expressions

A combination of numbers and expressions; may contain addition, subtraction, multiplication, division, parenthesis and exponents.

### Evaluate

Find the number that the expression represents.

### Order of Operations

Parenthesis
Exponents
Multiplication & Division (from left to right)
Addition & Subtraction (from left to right)

### Rational Numbers

Numbers that can be written in the form of a/b, where a & b are integers with b≠0. They include integers, fractions, terminating/repeating decimals, and perfect square roots.

ex: 2/3, 7, √16

### Irrational Numbers

Non-repeating, non-terminating decimals, and square roots of numbers that are not perfect squares.

ex: π, √7

### Perfect Squares

The product of a number times itself; the square roots are always integers.

ex: 1, 7, 9, 14

### Real Number Line

A number line on which every real number can be matched with a point on the line.

### Absolute Value

The distance a real number is from zero on a number line. Because it is distance, it is always positive.

### Rules for Adding and Subtracting Integers

1. Same signs you add and keep the sign.
2. Different signs you subtract and get the sign of the largest.

### Rules for Multiplying and Dividing Integers

1. Negative • negative = positive
2. Negative • positive = negative
3. Double negative = positive

### Inequality Symbols

Symbols used to order or compare real numbers.

### Rules for Adding and Subtracting Real Numbers

When they have the same sign:
add the numbers and keep the sign.

When the signs are different:
subtract the numbers and keep sign of the larger one.

### Rules for Multiplying and Dividing Real Numbers

Odd number of negatives:
multiply/divide and the result will be negative.

Even number of negatives:
multiply/divide and the result will be positive.

### Variables

Symbols used to represent numbers.

### Like Terms

Terms that contain the same variables; with corresponding variables having the same powers.

### Solution

A value that when substituted in an equation in place of a variable, makes the equation true.

### Ratio

A comparison of two numbers. It can be written as a/b, a:b, or a to b.

### Proportion

Two ratios that are equal, cross products are equal. (Money problems involving percent can also be solved by using this.)

-Can be used to calculate percent increase or decrease.

### Percent

Of one-hundred, (can be used to calculate discounts and tax).

### Direct Variation

Means that as x-up, y-up, or as x-down, y-down.

### Inverse Variation

Means that as x-up, y-down.

y = kx

y = k/x

L • W

B • H/2

πr2 (squared)

B1 + B2 • H/2

2πr or πd

### Perimeter of a Rectangle (formula)

2L + 2W (add all sides)

L • W • H

6s2 (squared)

L = 2πrh

### Surface Area of a Cylinder (formula)

SA = 2πrh + 2πr2 (squared)

1. More than
2. Less than
3. To
4. From

1. Sum of
2. Difference of

### Perimeter

Measures the distance around the object.

### Ordered Pair

A pair of numbers that describes a point's location on the coordinate plane.

### X-axis

The horizontal axis, side to side.

### Y-axis

The vehicle axis, up and down.

### Origin

The point where the y and x axis meet, (0,0)

The four parts of a graph; numbered counter clock wise (starting with the upper, right quadrant).
If the ordered pair is exactly on either the y or x axis it has no quadrant, (none).

Q1: (+,+)
Q2: (-,+)
Q3: (-,-)
Q4: (+,-)

### Translation

A "slide" that moves the graph to a new position horizontally and/or vertically on the coordinate plane.

### Reflection

Flips a figure over a line of reflection.

### Relation

A set of ordered pairs.
Can be expressed in four different ways:
1. Ordered pairs
2. Graph
3. Table
4. Mapping

### Domain

A set of first coordinates in a relation.
(7,5) domain: 7

### Range

A set of second coordinates in a relation.
(7,5) range: 5

### Function

A relation in which none of the first coordinates repeat. (All of the Xs are different.)
Can be a rue with input values (the domain) and output values (the range).

### Linear Function

A function whose graph is a line function.

### Slope

Measures the steepness of a line. (The rate of vertical change to horizontal change.)

### Slope (formula)

(X1,Y1) and (X2,Y2)

M = ∆Y/∆X (Y2-Y1/ X2-X1)

### Line (formula)

y = mx+b

where 'm' represents the slope and 'b' (0,#) represents the y-interpret.