A | B | C | D | E | F | G | H | I | K | L | M - Z

A
A.M. Abbreviation that indicates time from midnight to noon.
Ab/c key A calculator key used to change an improper fraction to a mixed number.
abacus A counting frame to aid in mathematical computation.
about Key word used to indicate that an estimate is needed.
acute angle An angle that measures less than 90º.
acute triangle A triangle with three acute angles.
addend Any one of a set of numbers to be added.
addition A joining operation on two or more numbers that gives a total; the sum.
addition equation An equation that involves addition.
addition expression A mathematical expression that contains only numbers and a plus sign (+).
adjusted estimate After a rough estimate is made, the back digits (the digits to the right of the front digits of a number) are used to adjust or refine an estimate of a sum.
algebraic expression A mathematical expression that contains one or more variables.
analogy A mathematical expression involving two sets where the relationship between the parts of the first set is the same as the relationship between the parts of the second set. (e.g., 1 is to 4 as 10 is to 40).
angle A figure formed by two rays that have a common endpoint.
angle bisector A ray that bisects an angle into two congruent parts.
arc The curved path between any two points on a circle.
area The number of square units needed to cover a flat surface.
array A number of objects arranged in rows and columns, used to model multiplication.
associative (grouping) property Changing the grouping of the addends (or factors) does not change the sum (or product).
average The quotient obtained by dividing a sum by the number of addends. Also called mean.
axis The horizontal or vertical number line of a graph.
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B
BACK (BK) A LOGO command that tells the LOGO turtle to move back a given number of steps.
bar graph A graph that uses bars to show data. The bars may be of different lengths.
base One of the equal factors in a product; a selected side or face of a geometric figure.
BASIC An acronym for Beginner's All-purpose Symbolic Instruction Code; a computer language used to process information.
benchmark An object of known measure used to estimate the measure of other objects.
better buy The product which costs less after comparing the unit costs.
billion 1,000,000,000
bisect To divide a line segment or an angle into two congruent parts.
box-and-whisker plot A diagram that analyzes data using the range of the set. It consists of a number line, a center mark to represent the median, a "box" between the quartiles, and two "whiskers" that extend to the extremes.
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C
cancellation The dividing of any numerator and denominator of a set of fractions by their greatest common factor before multiplying.
capacity The amount, usually of liquid, a container can hold.
cell The basic unit of an computer spreadsheet; the intersection of a column and a row.
Celsius (ºC) scale The temperature scale in which 0ºC is the freezing point of water and 100ºC is the boiling point of water.
center The point that is the same distance from every point on a circle.
centi- A prefix meaning hundredth. (e.g., 1 centimeter = 1/100 of a meter)
centigram (cg) A metric unit used to measure mass; 100 cg = 1 g.
centiliter (cL) A metric unit used to measure capacity; 100 cL = 1 L.
centimeter (cm) A metric unit used to measure length; 1 cm = 10 mm.
centiquad A manipulative, also known as a unit, used to represent a unit of measure in the decimal system. 
10 centiquads = 1 deciquad; 100 centiquads = 1 quad.
central angle An angle whose vertex is the center of a circle.
century (cent.) A unit used to measure time; 100 y = 1 cent.
certain event An event whose outcome is certain to occur. Its probability is 1.
chord A line segment with both endpoints on a circle.
circle A simple closed curve in which all the points are the same distance from a point called the center.
circle graph A graph that uses the area of a circle to show the division of a total amount of data.
circumference The distance around a circle.
classify To categorize or sort a set of objects, numbers, or other things according to some common attribute.
closed figure A figure that has no openings.
closed statement A statement that can be judged true or false.
cluster Numbers in a set that group around the same number.
combination A group of subsets of a set without regard to order (e.g., in the set consisting of A, B, and C, {A,B} and {B,A} are the same combination).
combined event An event in probability that is made up of two events joined by the words or, and, or not.
Combining Strategies A strategy that requires the problem solver to interpret given information, then select and combine appropriate strategies to solve a problem.
command A word that tells a computer what to do.
commission Money earned equal to a percent (%) of the selling price of items sold.
common denominator A number that is a multiple of the denominators of two or more fractions.
common factor A number that is a factor of two or more numbers.
common multiple A number that is a multiple of two or more numbers.
commutative (order) property Changing the order of the addends (or factors) does not change the sum (or product).
compare To determine similarities and differences of objects; to determine whether a number is less than, equal to, or greater than another number.
compass An instrument used to draw circles.
compatible numbers Numbers that are easy to compute with mentally.
complementary angles Two angles the sum of whose measures is 90º.
complex fraction A fraction whose numerator or denominator (or both) is a fraction or a mixed number.
composite number A whole number greater than 1 that has more than two factors.
compound event An event in probability that involves two or more events that are considered as a single event. One event follows the other.
compound figures Figures formed by the intersection of two or more regular polygons.
compound statement A statement in logic comprised of two statements joined by the word and or the word or.
computer A programmable electronic device that can store, retrieve, and process data.
computer program A set of commands and statements that tell a computer what to do.
computer spreadsheet A computer program that arranges data in a column-and-row format.
concave polygon A polygon with one or more diagonals that have points outside the polygon.
cone A space, or solid, figure with one circular base, one vertex, and a curved surface.
congruent (-) A word or symbol used to indicate equivalency of measure.
congruent figures Figures that have the same size and shape.
conjunction A compound statement formed by joining two statements with the connective and.
constant function A calculator key that stores an operation and number in a calculator. Each time this key is pressed, the operation and the number following it are repeated in the value in the display.
convex polygon A polygon whose diagonals do not have any points outside the polygon.
coordinate plane A grid divided into four quadrants used to locate points by naming ordered pairs.
coordinates An ordered pair of numbers used to locate a point on a grid.
corner An angle; two rays with a common endpoint; the point on a plane figure where two sides meet; the point on a space (or solid) figure where three or more edges meet.
corresponding angles The matching angles of congruent figures.
corresponding parts The matching sides and angles of congruent figures.
corresponding sides The matching sides of congruent figures.
counting backwards To name numbers in descending order.
counting on To name numbers in ascending order.
cross products The products obtained by multiplying the numerator of one fraction by the denominator of a second fraction and the denominator of the first fraction by the numerator of the second fraction.
cube A space, or solid, figure with six congruent square faces.
cubed A number multiplied by itself three times.
cubic centimeter (cm³) A metric unit used to measure volume; 1 cm³ = 1000 mm³; 
10 000 cm³ = 1 m³.
cubic decimeter (dm³) A metric unit used to measure volume; 1 dm³ = 1000 cm³; 1000 dm³ = 1 m³.
cubic foot (ft³) A customary unit used to measure volume; 1 ft³ = 1728 in.³; 27 ft³ = 1 yd³.
cubic inch (in.³) A customary unit used to measure volume; 1728 in.³ = 1 ft³.
cubic meter (m³) A metric unit used to measure volume; 1 m³ = 1 000 000 mm³; 1 m³ = 1000 dm³.
cubic millimeter (mm³) A metric unit used to measure volume; 1000 mm³ = 1 cm³.
cubic unit A unit used to measure volume.
cubic yard (yd³) A customary unit used to measure volume; 1 yd³ = 27 ft³.
cup (c) A customary unit used to measure capacity; 1 c = 8 fl oz; 
2 c = 1 pt; 4 c = 1 qt.
curved surface A surface that is not flat.
customary system The measurement system that uses inch, foot, yard, and mile; fluid ounce, cup, pint, quart, and gallon; ounce, pound, and ton.
cylinder A space, or solid, figure with two parallel, congruent circular bases and a curved surface.
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D
DATA A statement in BASIC that stores a list of items used by READ statements.
data Facts or information.
database A group of facts and figures that are related and can be arranged in different ways.
database A large collection of data that is organized and stored in a manner that facilitates quick, easy retrieval.
day (d) A unit used to measure time; 24 h = 1 d; 7 d = 1 wk; 365 d = 1 y.
decagon A polygon with ten sides.
deci- A prefix meaning tenth. (e.g., 1 decimeter = 1/10 of a meter)
decigram (dg) A metric unit used to measure mass; 1 dg = 10 cg; 10 dg = 1 g.
deciliter (dL) A metric unit used to measure capacity; 1 dL = 10 cL; 10 dL = 1 L.
decimal A number with a decimal point separating the ones from the tenths place.
decimal point A point used to separate ones and tenths in decimals.
decimeter (dm) A metric unit used to measure length; 1 dm = 10 cm; 
1 dm = 100 mm.
decimeter cube A manipulative used to represent a metric measure of volume, 1 dm3.
deciquad A manipulative, also known as a rod, used to represent a unit of measure in the decimal system. 1 deciquad = 10 centiquads; 10 deciquads = 1 quad.
degree (°) A unit used to measure angles; a unit used to measure temperature on the Celsius (ºC) or the Fahrenheit (ºF) scale.
degree Celsius (°C) A unit on the Celsius (°C) scale for measuring temperature.
degree Fahrenheit (°F) A unit on the Fahrenheit (°F) scale for measuring temperature.
deka- A prefix meaning ten. (e.g., 1 dekameter = 10 meters)
dekagram (dag) A metric unit used to measure mass; 1 dag = 10 g; 100 dag = 1 kg.
dekaliter (daL) A metric unit used to measure capacity; 1 daL = 10 L; 100 daL = 1 kL.
dekameter (dam) A metric unit used to measure length (l) or distance; 1 dam = 10 m; 100 dam = 1 km.
denominator The number below the bar in a fraction.
dependent events Events in probability such that the outcome of one event depends on the outcome of another.
diagonal A line segment, other than a side, that joins two vertices of a polygon.
diameter A line segment that passes through the center of a circle and has both endpoints on the circle.
difference The answer in subtraction.
digit Any one of the numerals 0, 1, 2, 3, 4, 5, 6, 7, 8, or 9.
discount A reduction on the regular, or list, price of an item.
disjunction A compound statement formed by joining two statements with the connective or.
display The window on a calculator that shows the information entered.
distributive property Multiplying a number by a sum is the same as multiplying the number by each addend of the sum and then adding the products.
dividend The number to be divided.
divisible A number is divisible by another number if the remainder is 0 when the number is divided by the other number.
division As sharing: a given set is partitioned into a specified number of groups to determine how many are in each equal group. 
As separating: a given set is partitioned by a specified amount to determine how many equal groups.
division expression A mathematical expression that involves division.
division sentence A number sentence that involves division.
divisor The number by which the dividend is divided.
dollar ($) A U.S. monetary unit equal in value to 100 cents (100¢), and represented by the one dollar bill (or coin); 1 dollar = 100 pennies; 1 dollar = 20 nickels; 1 dollar = 10 dimes; 1 dollar = 4 quarters.
double bar graph A graph that uses pairs of bars to compare two sets of data.
double line graph A graph that uses pairs of line segments to compare two sets of data.
doubles fact An addition or subtraction fact in which the parts are the same. (e.g., 3 + 3 = 6; 8 - 4 = 4)
downward slope The slope of a linear function whose second coordinate consistently decreases.
Draw a Picture A problem-solving strategy that involves modeling by drawing a picture in order to make comparisons or complete computations.
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E
edge The line segment where two faces of a space figure meet.
elapsed time The amount of time between two given times.
END A BASIC command that tells the computer it has reached the end of a program.
endpoint The point at the end of a line segment or ray.
equal parts Portions that are the same size and the same shape.
equalize To make groups equal by adding more or taking away objects.
equation A statement that two mathematical expressions are equal.
equilateral triangle A triangle with three congruent sides and three congruent angles.
equivalent decimals Different decimals that name the same amount.
equivalent fractions Fractions that name the same amounts.
estimate An approximate answer; to find an answer that is close to the exact answer.
evaluate To find the number that an algebraic expression names.
even number A whole number divisible by 2.
event A set of one or more outcomes of a probability experiment.
expanded form The written form of a number that shows the place value of each of its digits.
expanded scale A scale of a graph that does not begin at the origin, and/or has exaggerated increments. It can be used to mislead or misinterpret data.
exponent A number that tells how many times another number is, to be used as a factor.
Extra Information A problem-solving strategy that requires the distinction between relevant and irrelevant information to solve a problem.
extremes The greatest and least numbers in a set of data; a name for parts of a proportion [in the proportion a/b = c/d, a and d are extremes (b and c are means)].
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F
face A flat surface of a space figure.
fact family A set of related addition and subtraction (or multiplication and division) facts that use the same numbers (e.g., 3, 4, 7: 3 + 4 = 7, 4 + 3 = 7, 7 - 4 = 3, 7 - 3 = 4; 2, 3, 6: 2 x 3 = 6, 3 x 2 = 6, 6 � 3 = 2, 6 � 2 = 3).
factor One of two or more numbers that are multiplied to form a product.
factor pair Two numbers that are multiplied to give a specific product.
factor tree A diagram used to find the prime factors of a number.
Fahrenheit (ºF) scale The temperature scale in which 32ºF is the freezing point of water and 212ºF is the boiling point of water.
field In a database, an assigned area designated for a specific category of data.
file In a database, an organized collection of related data, comprised of records.
Find a Pattern A strategy in which the problem solver must discover the pattern and, in most cases, extend it in order to solve the problem.
flat surface A surface that is not curved.
flip To turn a figure to its reverse side.
flip image The second figure that results after a flip occurs to a first figure. The flip image is congruent (-) to the original figure. Also known as a mirror image.
flip line The imaginary line over which a figure is flipped to form its mirror image, or flip image. Also called the line of reflection.
flowchart A diagram that shows a step-by-step progression through a procedure or system.
fluid ounce (fl oz) A customary unit used to measure capacity; 8 fl oz = 1 c; 16 fl oz = 1 pt.
foot (ft) A customary unit used to measure length (l) or distance; 1 ft = 12 in.; 3 ft = 1 yd; 5280 ft = 1 mi.
FOR ... NEXT loop BASIC statements that tell the computer to repeat program lines a given number of times.
formula A rule that is expressed by using symbols.
FORWARD (FD) A LOGO command that tells the LOGO turtle to move forward a given number of steps.
fraction A number that names a part of a whole, a region, or a set.
frequency table A chart that shows how often each item appears in a set of data.
front-end estimation A way of estimating by using the front, or greatest, digits to find an approximate answer.
function A set of ordered pairs in which no two ordered pairs have the same first coordinate.
function table A chart that shows how a first quantity depends on a second quantity.
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G
gallon (gal) A customary unit used to measure capacity; 1 gal = 4 qt; 1 gal = 8 pt.
googol The figure 1 followed by 100 zeroes, equal to -.
googolplex The figure 1 followed by a googol of zeroes, equal to googolplex.
GOTO A statement in BASIC that tells the computer to branch to a specific line.
graduated cylinder A tool used to measure capacity.
gram (g) A metric unit used to measure mass; 1 g = 1000 mg.
graph A drawing that shows a relationship between certain sets of numbers.
greatest common factor (GCF) The greatest number that is a factor of two or more numbers.
Greenwich mean time (GMT) The time at the prime meridian (0° longitude), used as the world's standard time.
grid A network of perpendicular lines used to locate points.
Guess and Test A problem-solving strategy that requires the problem solver to guess a solution, test its correctness, and refine the guess using logical reasoning.
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H
half gallon One half of the customary unit gallon (gal) used to measure capacity; 1 half gallon = 2 qt; 2 half gallons = 1 gal.
half inch One half of the customary unit inch (in.) used to measure length (l); 2 half inches = 1 inch.
half turn A turn that causes a figure to face in the opposite direction; a turn of 180º.
half-turn symmetry The symmetry that occurs when a figure is turned halfway (180º) around its center point and the figure that results looks exactly the same.
hecto- A prefix meaning hundred. (e.g., 1 hectometer = 100 meters)
hectogram (hg) A metric unit used to measure mass; 1 hg = 100 g; 10 hg = 1 kg.
hectoliter (hL) A metric unit used to measure capacity; 1 hL = 100 L; 10 hL = 1 kL.
hectometer (hm) A metric unit used to measure length (l) or distance; 1 hm = 100 m; 10 hm = 1 km.
height The perpendicular distance between the bases of a geometric figure. In a triangle, the perpendicular distance from the opposite vertex to the line containing the base.
heptagon A polygon with seven sides.
hexagon A polygon with six sides.
hexagonal prism A prism with two parallel hexagonal bases.
hexagonal pyramid A pyramid with a hexagonal base.
Hidden Information A strategy that requires the problem solver to discover a piece of information not directly stated in the problem that is necessary to solve it.
higher terms A fraction is in higher terms than its equivalent fraction when its numerator and denominator are greater than the numerator and denominator of its equivalent fraction.
HOME A LOGO command that puts the LOGO turtle back in its starting position.
hour (h) A unit used to measure time; 1 h = 60 min; 24 h = 1 d.
hundredth 1/100
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I
identity property Adding 0 to a number or multiplying a number by 1 does not change the number's value.
IF-THEN A statement in BASIC that makes a decision that affects the flow of the program based on the result of an expression.
impossible event An event whose outcome has no chance of occuring. Its probability is 0.
improper fraction A fraction with its numerator equal to or greater than its denominator.
inch (in.) A customary unit used to measure length (l); 12 in. = 1 ft.
independent events Events in probability such that the outcome of one event does not depend on the outcome of another.
inequality A statement that two mathematical expressions are not equal. It uses an inequality symbol: <, >, or -.
INPUT A BASIC command that tells the computer to wait for a response from the user.
Integer-divide key A calculator key that divides two whole numbers and displays the result as a quotient (Q) and remainder (R).
integers The whole numbers and their opposites.
Interpret the Remainder A strategy that requires the problem solver to write a division sentence based on a problem, solve the sentence, and then examine the remainder in order to solve the problem.
intersecting lines Lines that meet or cross.
interval The number of units between spaces on a graph's scale.
intervals The equally spaced increments on the scale of a graph.
inverse operations Mathematical operations that undo each other, such as addition and subtraction or multiplication and division.
irregular figure A closed figure without a center, whose sides are not line segments.
is greater than (>) The term or symbol used to indicate an inequality in which the first amount has a greater value than the second amount. (e.g., 16 is greater than 12; 2 + 3 > 1 + 0)
is less than (<) The term or symbol used to indicate an inequality in which the first amount has a lesser value than the second amount. (e.g., 12 is less than 16, 1 + 0 < 2 + 3)
isosceles right triangle A triangle with two congruent sides, two congruent angles (45°), and one right angle (90°).
isosceles triangle A triangle with two congruent sides and two congruent angles.
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K
key A list of words or phrases that explains the symbols used in a table.
keyboard Part of a computer used to input information.
kilo- A prefix meaning thousand. (e.g., 1 kilometer = 1000 meters)
kilogram (kg) A metric unit used to measure mass; 1 kg = 1000 g; 1000 kg = 1 t.
kiloliter (kL) A metric unit used to measure capacity; 1 kL = 1000 L.
kilometer (km) A metric unit used to measure distance; 1 km = 1000 m.
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L
leap year A special unit used to measure time; 1 leap year = 366 days, and occurs once every four years (e.g., 1992, 1996, 2000, etc.).
least common denominator (LCD) The least common multiple of the denominators of two or more fractions.
least common multiple (LCM) The least number, other than 0, that is a common multiple of two or more numbers.
LEFT (LT) A LOGO command that tells the LOGO turtle to turn left a given number of degrees.
length The measure of distance between two points.
length (l) The measure of a horizontal dimension of a space figure; the measure of distance between two points.
LET A BASIC statement that assigns a value to a variable.
line A set of points in order extending indefinitely in opposite directions.
line graph A graph that uses points on a grid connected by line segments to show data.
line numbers A line in a computer program that tells the computer what to do.
line of reflection Another name for a flip line.
line of symmetry A line that divides a figure into two congruent parts.
line plot A diagram that organizes data on a number line.
line segment A part of a line that has two endpoints.
linear function A function that, when graphed, produces a straight line.
linear measure A measure of length.
liter (L) A metric unit used to measure capacity; 1 L = 1000 mL.
Logic and Analogies A problem-solving strategy that combines reasoning skills of the Logical Reasoning strategy with the use of an analogy in order to solve a problem.
Logical Reasoning A problem-solving strategy that involves using clues given in a problem in order to eliminate information until the correct solution is arrived at.
LOGO A computer language that can be used to draw figures.
LOGO turtle A graphic element used to indicate the position of the cursor in a LOGO program.
lowest terms A fraction is in lowest terms when its numerator and denominator have no common factors other than 1.
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