• Absolute Value:  distance from 0

ว-6ว is read “the absolute value of negative six” and equals 6

Acute Angle:  an angle whose measure is less than 90º

Acute Triangle:  a triangle with 3 acute angles

Angle:  formed when two rays have the same endpoint (vertex).  An angle can be named by its vertex with an angle symbol or using 3 points on the angle with the vertex in the middle

Area:  the amount of space inside a closed two-dimensional (flat) figure measured in square units such as in², cm², or m²

Average:  the mean, found by dividing the sum of a set of numbers by the amount of numbers in the set  (in other words, add all the numbers and divide that answer by how many numbers there are)

Bar Graph:  a graph that compares different amounts using bars

Base:   (1) in a two-dimensional figure, the base must meet the height at a right angle  (and is not always on the bottom)

(2) In a prism, the bases are polygons that are parallel and congruent (same size and shape) and located on opposite sides.

(3) In a pyramid, the base shares an edge with every other face

(4) a number with an exponent which is used as a factor in multiplication (the 5 in 5²)

Circle:  a two dimensional shape in which every point is the same distance from the center

Circle (or Pie) Graph:  a graph in the form of a circle cut into “slices” like a pie to show parts of a whole

Circumference:  the distance around a circle

Composite:  a number with more than 2 factors

Cone:  a three-dimensional figure with a circle as a base and one vertex (an ice cream sugar cone)

Constant of Proportionality:  A ratio of the change in y divided by the change in x that only exists when the point (0, 0) is included.  The constant of proportionality is the "k" in the equation y = kx.

Coordinate Graph:  a graph with two axes (x- and y-) where every point can be named by giving the x and y values

Cube Root:  a number that, when used as a factor 3 times, equals the given number  (For example, 2 is the cube root of 8 because 2 x 2 x 2 = 8.)  The cube root symbol looks like a square root symbol but with a small three on the left side of it.)

Cylinder:  a three-dimensional figure with two congruent and parallel circles at opposite ends (a can of soup)

Denominator:  the bottom number of a fraction

Diameter:  a line segment from a point on a circle through the center to a point on the circle on the opposite side  The diameter is twice as long as the radius.

Divided evenly:  division with no remainder

Decagon:  a ten-sided polygon

Difference:  the answer to a subtraction problem

Dividend:  the first number in a division problem, the total amount being divided, or the number that is inside the division house

Divisor:  the second number in a division problem or the number outside the division house

Equation:  two expressions with an equals sign between them

Equilateral Triangle: a triangle with 3 equal sides and 3 equal angle measures

Evaluate:  find the value of, usually indicating to replace a variable with a given number and simplify (find the answer)  For example, if asked to evaluate 3x - 7 when x = 4, replace the x with a 4 to have:  3 times 4 - 7, which equals 12 - 7 which equals 5.

Expanded Form:  a way of writing a math problem without using exponents

For example, the expanded form of 5³ is 5×5×5

Exponent:  a number that tells how many times to use the base as a factor (the 2 in 5²)

Exponential Form:  a base number with an exponent

Expression:  a number, variable, or any combination of numbers and letters that are being added, subtracted, multiplied, or divided  (Ex:  5, x, -2y, 3x – 8)

Face:  a side of a prism

Factor:  a number in a multiplication problem; a number that divides without a remainder into another number.  (For example, 3 is a factor of 21 because 21 divided by 3 equals a whole number, 7.)

Fraction:  a part of a number written as a quotient using a bar over the whole amount .  (For example, ¾ means that 3 parts are being considered when 4 parts make the whole.)

Greatest Common Factor (GCF):  the largest number that divides evenly (without a remainder) into 2 or more numbers.  (For example 5 is the greatest common factor of 15 and 40.)

Heptagon:  a seven-sided polygon

Hexagon:  a six-sided polygon

Hypotenuse:  the longest side in a right triangle

Improper Fraction:  a fraction in which the numerator is equal to or larger than the denominator

Inequality:  two expressions with a greater than (>), less than (<), greater than or equal to (≥), or less than or equal to (≤) sign between them

Integers:  whole numbers and their opposites       { . . . -4, -3, -2, -1, 0, 1, 2, 3, 4, …}

Interval:  the difference between two marked spaces on a number line that should be equal for any two consecutive markings

Inverse operations:  operations that “undo” each other such as addition and subtraction or multiplication and division

Irrational Numbers:  numbers when, in decimal form, continue forever without repeating or terminating

Isosceles Triangle:  a triangle with at least 2 equal sides and 2 equal angle measures

Least Common Multiple (LCM):  the smallest number that can be divided evenly by two or more given numbers.  (For example the LCM of 4 and 6 is 12.)

Line:  a straight path that continues forever in two directions.  A line is named with two points on the line (capital letters) and a line with arrows on both ends above them

Line Graph: a graph where points of information are connected, generally showing change over time

Line Plot:  a way of displaying information with different categories or amounts on a number line using vertical x’s to show how many of the category or number.  (For example, a line plot could be used to show how many students have a favorite color such as pink, blue, purple, orange, green, red, or yellow or a line plot could be used to show the number of siblings each student has.)

Lowest Terms:  a fraction that cannot be simplified

Mean:  the average, found by dividing the sum of a set of numbers by the amount of numbers in the set

Measures of Central Tendency:  a measure of the “middle” of a set of data (including mean, median, and mode)

Median:  the middle number in a set of ordered numbers.  If there are two numbers in the middle, the median is the number exactly between the two which can be found by averaging them.

Mode:  the number that occurs most often in a set of numbers.  A set can have no mode, one mode, or more than one mode.

Multiple:  a number that can be divided evenly by another number.  (For example, 21 is a multiple of 7.)

Natural (Counting) Numbers:  {1, 2, 3, 4, 5, . . . }

Nonagon:  a nine-sided polygon

Numerator:  the top number of a fraction

Obtuse Angle:  an angle whose measure is more than 90º

Obtuse Triangle:  a triangle with an obtuse angle

Octagon:  an eight-sided polygon

Opposite:  change in a number from positive to negative or negative to positive

Ordered Pair:  an x-coordinate and y-coordinate to indicate a point on a coordinate graph.  For example, the ordered pair (5, -2) is located by finding 5 on the x-axis (horizontal line) and moving down 2.

Origin:  the point on a coordinate graph where the x-axis and y-axis intersect

Outlier:  a number in a set of numbers that is far away from the others

Parallelogram:  a quadrilateral with two pairs of parallel sides

Pentagon:  a five-sided polygon

Percent:  parts per hundred, the percent symbol (%) is written after a number

Percent Increase:  the amount of increase divided by the original amount expressed in parts per hundred

Percent Decrease:  the amount of decrease divided by the original amount expressed in parts per hundred

Perimeter:  the distance around a polygon

Pi:  a ratio of the circumference of a circle to its diameter

Pictograph:  a way of displaying information using symbols (or pictures) to show frequency

Plane:  a flat surface

Point:  a location in space, generally named with a capital letter in geometry or with an ordered pair on a coordinate graph

Polygon:  a closed plane figure made up of line segments that intersect at their endpoints

Prime:  a number with only two factors, 1 and itself

Prime factorization:  a number written as the product of prime numbers.  (Often, a factor tree is used to find prime factorization.  The prime factorization of 12 can be written 2×2×3 or with exponents as 2² · 3)

Prism:  a three-dimensional figure in which all faces are polygons and with at least one pair of opposite sides parallel and congruent

Product:  the answer to a multiplication problem

Proportion:  two equal ratios

Pyramid:  a three-dimensional figure with a base that shares an edge with every other face.  All faces except for the base come together at a common vertex

Pythagorean Theorem:  the sum of the squares of the legs in a right triangle is equal to the square of the hypotenuse, generally written as a² + b² = c² where a and b are the legs (sides that meet at the right angle) and c is the hypotenuse (longest side in a right triangle)

Quadrant:  a section of a coordinate graph with the x-axis and y-axis as borders  The quadrants are numbered with Roman numerals.  The first is the upper right corner where both x and y values are positive.  The others are numbered counter-clockwise (with the second being the upper left corner of the graph).

Quotient:  the answer to a division problem

Radius:  a line segment from the center of a circle to a point on the edge of the circle

Range:  the difference between the highest and lowest number in a set of numbers

Ratio:  a comparison of two numbers that can be written several ways

For example, a ratio of 5 boys to 6 girls can be written 5 to 6, 5:6, or as a fraction 5/6

Rational Numbers:  any number that can be written as a fraction.  All whole numbers and integers are rational numbers as well as any decimal that either repeats or terminates (ends).

Ray:  part of a line containing one endpoint named with two letters.  The first letter is the starting point of the ray, and the second letter is located on the ray.  An arrow pointing right is drawn above the two capital letters

Rectangle:  a parallelogram with four right angles

Rectangular Prism:  a prism with rectangular bases  (looks like a cereal box)

Reflection:  a flip

Rhombus:  a parallelogram with four equal sides

Right Angle: an angle whose measure is equal to 90º

Right Triangle:  a triangle with a right angle

Rotation:  a turn

Scale:  on a graph, the numbers given at fixed intervals; when looking at similar figures or a map, the scale can refer to the ratio of the length on one shape to its corresponding length on the other

Segment:  part of a line with two endpoints.  A segment is named by its endpoints (capital letters)

Simplify:  make more simple, usually by combining  numbers using the order of operations but, for a fraction, simplify would mean to divide the numerator and denominator by a common factor

Sphere:  a three-dimensional figure in which all points are the same distance from the center (a ball)

Square:  a rectangle with four equal sides

Square Root:  a number that, when multiplied by itself, equals the given number

Scalene Triangle: a triangle with 3 different side lengths and 3 different angle measures

Scatterplot:  a coordinate graph with ordered pairs plotted to show a relationship between two variables

Scientific Notation is used for very large or very small numbers

A number in scientific notation is written as the product of two numbers.  The first number is greater than or equal to one but less than 10.  The second number is written as a power of 10.

Standard Form:  writing a number the “normal” way using digits

Straight angle:  an angle whose measure is equal to 180º

Surface Area:  the total of the areas of the surfaces of a three-dimensional figure

Tally Marks:  marks used to count information by writing four vertical lines and then the fifth mark crosses the four so that they can easily be totaled counting by fives.

Terminating:  ending

Transformation:  the reflection, rotation, or translation of a figure

Translation:  a slide

Trapezoid:  a quadrilateral with at least one pair of parallel sides

Trend:  if as one variable increases, the other variable increases, this is a positive trend.  If one variable increases as the other decreases, this is a negative trend

Triangle:  a polygon with 3 sides

Triangular Prism:  a prism with triangular bases

Variable:  a letter used in place of a number

Vertex:  a point where two lines, rays, or segments intersect

Volume:  the amount of space inside a three-dimensional figure measured in cubic units such as in³, cm³, or ft³

Whole Numbers:  {0, 1, 2, 3, 4, . . . }

x-axis:  the horizontal number line on a coordinate graph

y-axis:  the vertical number line on a coordinate graph