
Absolute Value: distance from 0
ว6ว 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 twodimensional (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 twodimensional 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 threedimensional 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 threedimensional 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 tensided 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 sevensided polygon
Hexagon: a sixsided 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 ninesided 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 eightsided polygon
Opposite: change in a number from positive to negative or negative to positive
Ordered Pair: an xcoordinate and ycoordinate to indicate a point on a coordinate graph. For example, the ordered pair (5, 2) is located by finding 5 on the xaxis (horizontal line) and moving down 2.
Origin: the point on a coordinate graph where the xaxis and yaxis 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 fivesided 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 threedimensional 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 threedimensional 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 xaxis and yaxis 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 counterclockwise (with the second being the upper left corner of the graph).
Quadrilateral: a foursided polygon
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 threedimensional 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
Sum: the answer to an addition problem
Surface Area: the total of the areas of the surfaces of a threedimensional 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 threedimensional figure measured in cubic units such as in³, cm³, or ft³
Whole Numbers: {0, 1, 2, 3, 4, . . . }
xaxis: the horizontal number line on a coordinate graph
yaxis: the vertical number line on a coordinate graph