Mathematics Vocabulary

Term	Grade / Topic	Definition
Acute Angle	3rd/G 5th/M	Any angle that measures between 0� and 90�.
Addends	3rd/AR	Numbers to be added.
Additive Property of Equality	5th/C&E	If you add the same number to each side of an equation, the two sides remain equal. If a = b, then a + c = b + c.
Algebra	5th/AR	A mathematical language that uses letters along with numbers. The letters stand for numbers that are unknown. x - 3 = 17 is an example of an algebra problem.
Algebraic Relationships	5th/AR	Patterns or connections between numbers, symbols, graphs and words.
Angle	3rd/M	Two rays with a common endpoint form an angle.
Area	3rd/M	The number of square units needed to cover a surface like a wall, floor or other two-dimensional shape.
Average		Usually referring to the mean of a set of numbers. The sum of the given set of numbers divided by the number of numbers.
Bar Graph	3rd/S&P	A graph that is used to compare quantities. The height or length of each bar represents a given number.
Capacity	3rd/M	How much liquid or pourable solid a container can hold (see volume).
Cartesian Graph (first quadrant)	5th/AR	A way of locating points in a space by using a number on a vertical line and a number on a horizontal line (similar to the game of battleship). The pairs of numbers are called ordered pairs, example (2, 1). The first number is horizontal (x), and the second is vertical (y).
Central Tendency	5th/S&P	The measures of mean, median, or mode.
Chord	3rd/G	A straight line with both endpoints on the circumference of a circle.
Circle Graph	5th/S&P	A graph used to compare parts of a whole. The circle represents the whole and is separated into parts of the whole.
Closed Figures	3rd/G	A figure where you can't get to the outside from the inside without going over a line.
Common Factor	3rd/AR	A number that is a factor of two or more numbers. Common factors of 2 and 8 are 1 and 2.
Common Multiples		Multiple that two or more numbers share. Some multiples of 2 are 2, 4, 6, 8, 10, 12. Some multiples of 3 are 3, 6, 9, 12. The first two common multiples of 2 and 3 are 6, and 12.
Composite Numbers		Numbers that have 3 or more factors.
Congruent		Figures with the same size and shape. Line segments that are equal in length.
Consecutive		Items that come after each other in a pattern. Example 2, 4, 6, 8 are consecutive even numbers.
Cube	3rd/G	A box-like figure whose faces are all square.
Cylinder	5th/G	A solid figure that has two circular bases. These bases are congruent and parallel. Examples include a can of vegetables or a Pringles potato chip container.
Denominators	5th/C&E	The number below the line in a fraction. The denominator represents the number of equal pieces the whole is broken into. Students need to be able to perform operations with fractional denominators of 2, 3, 4, 6, 8, 12, and 16.
Diameter	5th/G	The distance across a circle through its center.
Dilation	5th/G	When a figure is reduced or enlarged.
Dividend		The number being divided into equal groups.
Divisor		The number of equal groups or the number of items in each equal group.
End Point	3rd/M	The point at one end of a line segment or a ray.
Equation		A number sentence with an equal sign, 5 x 4 = 20.
Equivalent Fractions	5th/C&E	Two or more fractions with the same value. Example: 1/2 and 2/4.
Equivalent Questions for Word Problems	5th/C&E	Students should be able to take a word problem and write it correctly as a number sentence.
Even Numbers	3rd/C&E	A whole number that has 0, 2, 4, 6, or 8 in the one's place. Any number that can be divided into 2 equal groups of whole numbers.
Event	5th/S&P	The task or activity one does to explore outcomes in probability.
Experimental Probability	5th/S&P	The probability of an event based on actually doing the event or task.
Faces		Sides of a box.
Factor	5th/C&E	When two or more numbers are multiplied, each number is a factor of the product. In 5 x 3 = 15, 5 and 3 are factors and 15 is the product. A whole number that divides a number without any remainder.
Front-end Estimation	5th/C&E	A method used to estimate sums and differences by adding or subtracting the far left digits, and adjusting by looking at the sum or differences of what is left on the right. Example: In this problem you would add the far left digits of 5, 3, and 4 to get 12 and adjust using 232 + 8631000 9631000 12,000 + 2,000 = 14,000
Geometric Patterns	3rd/AR	When consecutive numbers of a sequence are formed by multiplying by the same factor. Example: 2, 4, 8, 16... each number is multiplied by 2 to get the next number.
Hexagons	3rd/G	A polygon with six sides.
Histogram	5th/S&P	A special kind of bar graph that displays the frequency of data that has been organized into equal number groupings. The number groupings cover all possible values of data, therefore there are no spaces between the bars.
Horizontal		Something arranged across (horizon).
Inequality		A number sentence that uses a greater than (>) less than (<), greater than or equal to (), or less than or equal to () sign. Example: 5 4 + y.
Inverse Property of Multiplication (i.e. reciprocal)	5th/C&E	Two numbers that have a product of 1. Example: the inverse or reciprocal of 2 is � because 2 x � = 1.
Line Graph	3rd/S&P	A graph used to show change and direction of change over a period of time.
Line Segments	3rd/G	Two endpoints and the straight path between them.
Mean	5th/S&P	The leveling-off or evening off of a set of data by taking from the larger number and giving to the smaller. It can be found by adding the data and dividing by the number of addends/terms.
Median	5th/S&P	The middle number when an odd number of terms is arranged from lowest to highest. If you have an odd number of terms and you arrange them from lowest to highest, median is the middle number. Example: 3, 7 8 10 12; 8 would be the median. If you have an even number of terms and you arrange them from lowest to highest, median is the "mean" of the 2 middle numbers. Example: 3, 7, 8, 10, 12, 15. 8 + 10 = 18 � 2 = 9 9 is the median.
Mode	5th/S&P	The number or item that appears most often in a set of data. There may be more than one mode or there may be no mode.
Multiples	5th/C&E, 3rd/AR	Numbers that are products of a given number and whole numbers. Some multiples of 6 are: 6, 12, 18, 24...
Multiplicative Property of Equality	5th/C&E	If each side of an equation is multiplied by the same number, then the two sides remain equal. If 3 = 2 + 1, then 3 x 4 = (2+1) x 4. And if a = b, then ac = bc.
Negative Integers	5th/C&E	Numbers less than zero; found to the left of zero on the number line (without decimals or fractions), example -2, -7, but not -2.5, or -2�
Nonstandard Units of Measurement	3rd/M	The use of any unit for measurement that is not normally used with measurement. Example: pencil, finger, piece of string, etc.
Number Line	3rd/S&P	A line with equal distances marked off to represent numbers.
Number Sentences	5th/AR	An equation or inequality with numbers. Example: 7 > 3 + 2, 6 3 x 3, and 8 = 9 - 1.
Numerators	5th/C&E	The number above the line in a fraction. The numerator represents how many pieces of the whole that are discussed.
Numeric Patterns	3rd/AR	Formed by adding or subtracting numbers instead of multiplying or dividing. Example: 3, 7, 11, 15 (adding 4 each time).
Obtuse Angle	3rd/G, 5th/M	Any angle that measures between 90� and 180�. Example:
Octagons	3rd/G	A polygon having eight sides.
Odd Numbers	3rd/C&E	A whole number that has 1, 3, 5, 7, or 9 in the ones place. Any number not evenly divisible by 2. A number that can't be divided into 2 equal groups of whole numbers.
Open Figures		Figures that aren't closed figures.
Open Sentences	5th/AR	A sentence that has a symbol or symbols that represent unknown numbers.
Order of Operations	5th/C&E	The rules to follow when more than one arithmetic operation is used. 1) Do all operations within grouping symbols first. 2) Do multiplication and division from left to right. 3) Do addition and subtraction from left to right.
Ordering of Numbers	3rd/C&E	Placing numbers in sequence, usually from smallest to largest.
Outcomes		Individual results of a probability experiment.
Parallel	5th/G	Lines going in the same direction and always being the same distance apart. If lines are parallel, they never meet or cross each other. Example: rails of a railroad track or the sides of a ladder.
Parallelogram	3rd/G	A quadrilateral (4-sided figure) that has both pairs of opposite sides equal and parallel. Example: all rhombi, (plural for rhombus). Squares and rectangles are parallelograms.
Pentagon	3rd/G	A polygon with five sides.
Perimeter	3rd/M	The perimeter of any closed figure is the distance around the outside of the figure.
Percent	5th/C&E	When a number is changed to a fraction with 100 in the denominator or hundredth. Example: 7% = 7/100 = 0.07
Perpendicular	5th/G	Two lines that intersect at right angles.
Pictographs	3rd/S&P	A kind of graph that uses pictures or symbols where each symbol or picture represents a certain number of some thing.
Planes	5th/G	A flat surface that goes on forever in all directions. Example: a never-ending table top.
Points	5th/G	A single exact location, often represented by a dot.
Polygon	5th/M	A two-dimensional figure formed by three or more line segments.
Predictions	5th/S&P	An educated guess about what will happen.
Prime	5th/C&E	A number, greater than 1, that has exactly 2 factors (1 and itself). (1 has only one factor so it is not prime.)
Probability	3rd/S&P	The ratio/fraction that tells how likely it is that an event will take place.
Product		Answer to a multiplication problem.
Pyramid	5th/G	A 3-dimensional figure whose base is a polygon and whose faces are triangles with a common point (called vertex).
Quadrilaterals	3rd/G	A polygon (2-dimensional figure) with four sides.
Quotient	5th/C&E	The number, other than the remainder, that is the result of division.
Radius	5th/G	The distance from the center of a circle to any point on the circle.
Ratio	5th/S&P	A comparison of two numbers. Example: 3 : 4, �, 3 to 4.
Rays	5th/G	A path that extends endlessly from one point in a certain direction. The arrow at the end of the ray indicates that the ray is endless. Example:
Rectangle	3rd/G	A quadrilateral with four right angles. (All squares are rectangles.)
Rectangular Solid	5th/G	A box.
Reflections	3rd/G	What something looks like in a mirror (a flip).
Rhombus	3rd/G	A quadrilateral with all four sides the same length. (All squares are rhombi.)
Right Angle	3rd/G 5th/M	An angle that has exactly 90�. Example: corner of 8� x 11 bond paper.
Rotations	3rd/G	Turning a figure around a point, (center of rotation is point).
Rounding	5th/C&E	Finding a number that is closer in tens, hundreds, thousands, (and so forth) to a given number on a number line.
Sample	5th/S&P	A randomly selected group chosen for the purpose of collecting data.
Similar Shapes/Similarity	3rd/G	Figures that have the same shape but different sizes.
Simulations	3rd/S&P	(work samples only - not on multiple choice until 5th grade) A way of acting out a problem by creating a situation like one in the real world.
Sphere	3rd/G	Three-dimensional figure with no faces, bases, edges, or vertices. All of its points are the same distance from a given point called the center.
Square	3rd/G	A parallelogram with all sides congruent and all angles are 90�. Please note: a square is a rectangle.
Standard Units of Measurement	3rd/M	Measurement units agreed upon by large groups of people, metric (gram, meter, liter) or standard (pound, yard, quart) forms of measurement.
Stem and Leaf Plot	5th/S&P	A frequency distribution made by arranging the data.
Symmetry Line	3rd/G	When a figure is folded along a center line, both parts are congruent, (fit exactly on top of each other).
Tables	3rd/S&P	A way to organize data in columns and rows.
Theoretical Probability	5th/S&P	The mathematically calculated chances of a specific event occurring (see probability). If P (H) =�, 100 tosses of a coin in theory should equal 50 heads.
Transformation	5th/G	Movement of geometric figures to new points in a coordinate system using reflection (flip), translation (slide), or rotation (turn).
Translation	5th/G	The new figure obtained by sliding a figure without flipping or turning it.
Triangles	3rd/G	A polygon with three sides.
Trapezoid	3rd/G	A quadrilateral with only one pair of parallel sides.
Variables	5th/AR	In a mathematical sentence, a variable is a symbol used to represent an unknown number, usually a lower case letter; y, a, b, x.
Vertical	3rd/S&P	Something arranged up and down.
Volume	3rd/M	The amount of space that a three-dimensional figure contains. Volume is usually expressed in cubic units, (how many small cubes would fit inside the figure.)

G = geometry	TOPICS	S&P = statistics and probability
C&E = calculation and estimation	M = measurement	AR = algebraic relationships

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