Glossary

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A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

Abacus: a counting device consisting of a frame holding a number of rods on which beads or other counters are free to slide.

Abscissa: in a Cartesian plane, the distance between any point and the vertical (y) axis. Also referred to as the x-coordinate.

Absolute value: the absolute value of a number x is 0 if x is equal to 0; if it is not zero, the absolute value is the positive member of the couple x and -x (in other words, the answer is always POSITIVE). Absolute value is usually indicated by bracketing a numeral with vertical lines.

For example:

|0| = 0

|5| = 5

|-8| = 8

Acute angle: an angle measuring less than 90 degrees.

Acute triangle: a triangle whose three angles are each less than 90 degrees.

Addition: the operation of combining two or more quantities to obtain a third quantity called their SUM. The plus sign (+) indicates addition.

Angle: the figure formed by two rays from the same endpoint.

Angle bisector: the line that divides an angle into two equal parts.

Approximate: close to the exact value; the symbol @ means "is approximately equal to".

Arc: a part of the circumference of a circle; for example, AB is an arc of the circle, centre O.

Area: the number of square units needed to cover a region.

Area of a parallelogram: the product of base and height; that is, area = base x height

Area of a rectangle: the product of length and width; that is, area = length x width

Area of a triangle: the product of one-half the base and height; that is area = 1/2 x base x height; or area = 0.5 x base x height.

Array: an arrangement of numbers in rows and columns; or an arrangement of small squares in a rectangle to illustrate a product of two numbers.

Ascending order: arranged in order from least to greatest.

Assumption: something that is accepted as true, but has not been proved.

Attribute: a quality or property of an object; such as color, size, shape, and so on.

Average: a single number that represents a set of numbers; see also mean, median and mode.

Axis (plural axes): the horizontal or vertical number line on a graph.

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Bar graph: a graph that displays data by using horizontal or vertical bars whose lengths are proportional to the numbers they represent.

Bar notation: the use of a horizontal bar over decimal digits to indicate that they repeat.

Base: the side of a polygon or the face of a solid from which the height is measured; the number that is the basic unit of a number system (as in our base 10 system).

Bias: in data analysis, an emphasis on characteristics that are not typical of the entire population.

Biased sample: a sample that is not representative of the population.

Bisector of a line segment: a line that divides a line segment into two equal parts; for example, the yellow line is a bisector of AB; see also perpendicular bisector.

Broken-line graph: a graph that displays data by using points joined by line segments

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Capacity: the amount a container can hold (usually expressed in litres).

Cartesian plane or coordinate plane: a two-dimensional surface on which coordinate axes are drawn.

Centimetre (cm): a metric unit used to measure length; there are 100 cm in 1 metre.

Centimetre cube: a cube 1 cm long, 1 cm wide, and 1 cm high.

Circle: a closed curve, all of whose points are the same distance from a point called the centre (O).

Circle graph: a diagram that uses sectors of a circle to display data.

Circumference: the distance around a circle or the circle itself.

Cluster: a section of a line plot in which there is at least one piece of data at each point on the number line.

Composite figure: a figure comprising different numbers or types of figures (in the example below, a triangle, a square and a rectangle).

Concrete graph: a graph comprising objects; for example, one pebble to represent one child.

Cone: a solid enclosed by a circular region and all line segments joining points on the boundary of the region to a point not in the region called the apex.

Congruent: figures that have the same size and shape, but not necessarily the same position.

Continuous data: data that can be represented as points on a Cartesian plane, such that the points can be joined with a straight line or a curve, to indicate that data values between the plotted points are possible; for example, if the side length and area of a square are plotted for whole number values of side length, the points can be joined because decimal values of side length and area are possible.

Coordinate axes: the x- and y-axes drawn at right angles on grid to represent a Cartesian plane.

Coordinate plane or Cartesian plane: a two-dimensional surface on which coordinate axes are drawn.

Coordinates: the numbers in an ordered pair that locate a point on a grid by indicating the distance and direction of the point from the x-axis and the y-axis.

Correlation: a relationship that exists between two quantities, in which they tend to change together, or opposite to each other; see negative correlation and positive correlation.

Cube (or hexahedron): a solid with six congruent, square faces that meet at right angles. It is one of the Platonic solids.

Cubic centimetre (cm³): a metric unit used to measure volume; there are 1 000 000 cm³ in 1 m³; when comparing volume and capacity, 1 cm³ is equivalent to 1 mL.

Cubic metre (m³): a metric unit used to measure volume; when comparing volume and capacity, 1 m³ is equivalent to 1000 L (or 1 kL).

Cubic millimetre (mm³): a metric unit used to measure volume; there are 1000 mm³ in 1 cm³.

Cubic units: units that measure volume.

Cuboctahedron: a solid with 14 faces; 6 of which are squares and 8 of which are equilateral triangles.

Curved solids: solids that are made up of at least one curved surface; for example, cones, cylinders and spheres are curved solids. A solid made up of only flat surfaces (no curved surface) is a polyhedron.

Cylinder: a solid with two parallel, congruent, circular bases.

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Data: facts or information.

Data table: facts or information presented in a table; the data in one row or column are usually related to the data in the adjacent row or column.

Decagon: a ten-sided polygon.

Decimal: a numeral that shows a fractional amount by using digits on either side of a dot called the decimal point; for example 0.7 is a decimal for 7/10 and 2.25 is a decimal for 9/4 or 2 1/4.

Decimal fraction: a fraction written in decimal form; for example, when the fraction 1/2 is written as 0.5, it is a decimal fraction.

Decimetre (dm): a metric unit used to measure length; one decimetre is 10 cm.

Denominator: the number below the line in a fraction; the denominator tells the number of parts into which the whole has been divided.

Descending order: arranged in order from greatest to least.

Diagonal: a line segment that joins two non-consecutive vertices of a figure, in other words it cannot be a side of the figure.

Diameter: the distance across a circle measured through the centre; or a line segment through the centre of a circle whose end points are on the circle.

Dilatation or enlargement: a copy of a figure or solid that is larger than the original figure or solid, but has the same shape.

Dimension: a measurement of length, width or height.

Dipyramid: the solid formed by joining two regular pyramids at one face.

Dodecagon: a twelve-sided polygon.

Dodecahedron: a solid that has 12 congruent faces (pentagons). It is one of the Platonic solids.

Double-bar graph: a bar graph that shows two sets of data.

Double broken-line graph: two broken lines that show two sets of data on the same axes.

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Edge: the line segment where two faces of a solid meet.

Enlargement or dilatation: a copy of a figure or solid that is larger than the original figure or solid, but has the same shape.

Equality: a statement that two numbers are equal; for example, 1/2 = 50/100.

Equation: a mathematical statement that two expressions are equal; for example 2 + x = 14.

Equilateral triangle: a triangle with three equal sides.

Equivalent expressions: different mathematical expressions, that represent the same number; for example, 14 + 6, 32 - 12, 4 x 5, and 40 ÷ 2 are all equivalent expressions for the number 20.

Equivalent fractions: fractions that have the same value; for example, 2/3 and 6/9.

Equivalent ratios: ratios that have the same value; for example, 1 : 2 and 5 : 10.

Estimate: to make a careful guess that is close to the actual value without calculating exactly.

Event: any set of outcomes of an experiment.

Experimental probability: the probability of an event calculated from experimental results; another name for the relative frequency of an event.

Exponent: a number that is placed to the right of and above another number; for example, 3 is the exponent in the expression 10³ and it indicates that the base 10 appears 3 times as a factor in the product 10 x 10 x 10.

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Face: a flat surface of a solid.

Figure: a two-dimensional geometrical diagram.

First-hand data: data collected by oneself.

Flip or reflection: a transformation that reflects a figure in a mirror line; the image is congruent to the figure but its orientation is the reverse of that of the original figure.

Formula: a rule that is expressed as an equation; for example speed = distance x time ( or S = d t ).

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Hexahedron: see cube.

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Icosahedron: a solid that has 20 congruent faces (triangles). It is one of the Platonic solids.

Irrational numbers: numbers with non-periodic and non-terminating decimals, that are mostly the result of square roots (and other roots) that cannot be taken precisely. For example, the square root of 2, and pi are irrational numbers.

Irregular polygon: a polygon that is not a regular polygon; for example, a rectangle, a parallelogram, any polygon that does not have all sides equal and all angles equal.

Isosceles acute triangle: a triangle with two equal sides and all angles less than 90 degrees.

Isosceles obtuse triangle: a triangle with two equal sides and one angle greater than 90 degrees.

Isosceles right triangle: a triangle with two equal sides and a 90 degree angle.

Isosceles triangle: a triangle with at least two equal sides.

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Key: an explanation on a bar graph of what the colours or shadings on the bars represent. See also legend.

Kilogram (kg): a metric unit used to measure mass; there are 1000 grams in 1 kg.

Kilolitre (kL): a metric unit used to measure capacity; there are 1000 litres in 1 kL.

Kilometre (km): a metric unit used to measure distance; there are 1000 metres in 1 km.

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Least common denominator (LCD): the least number that is a multiple of each of the given denominators; for example, 12 is the least common denominator for the fractions 1/3, 5/4 and 7/12.

Least common multiple (LCM): the least number that is a multiple of a set of numbers; for example, 24 is the least common multiple of 6 and 8.

Legend: the explanation of the symbols on a map; see also key.

Legs: the sides of a right triangle that form the right angle.

Line: a set of points in a straight path extending infinitely in both directions.

Line graph: see broken-line graph.

Line of best fit: a line drawn on a scatter-plot such that it passes through or as close as possible to as many points as possible.

Line plot: a number line on which each number in a set of data is plotted by making a mark (usually a cross or large dot) above that number on the number line.

Line segment: a part of a line between two points on the line.

Line symmetry: a figure that coincides with itself when it is reflected in a line is said to have line symmetry; for example, the dotted line is the line of symmetry for the figure below.

Litre: a metric unit used to measure capacity.

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Mass: the amount of matter in an object.

Maximum: the greatest number or amount.

Mean (x bar): the sum of a set of numbers divided by the number of numbers in the set; for example, 38 is the mean of the set of numbers 30, 44, and 40.

(30 + 44 + 40) / 3 = 38

Measure of central tendency: a single number that represents a set of data; see mean, median and mode.

Median (Med or Md): the middle number when an odd number of data are arranged in numerical order; for example, 11 is the median for the set of numbers 24, 10, 6, 11, 20.

6, 10, 11, 20, 24

11 is the middle number!

or, the mean of the two middle numbers when an even number of data are arranged in numerical order; for example, 12 is

the median for the set of numbers 13, 11, 6, 24, 20, 10.

6, 10, 11, 13, 20, 24

(11 + 13) / 2 = 12

Midpoint: the point that divides a line segment into two equal parts.

Millilitre (mL): a metric unit used to measure capacity; there 1000 mL in 1 L; when comparing capacity and volume, 1 mL is equivalent to 1 cubic centimetre.

Mixed number: a number comprising a whole number and a fraction; for example 6 2/3.

Mode (Mo): the number that occurs most often in a set of data; there can be more than 1 mode, or there can be no modes; examples:

1, 2, 2, 3, 3, 5, 5, 5, 6 The mode is 5

1, 2, 3, 5, 7, 8 There is no mode

1, 2, 2, 2, 3, 4, 5, 5, 5, 6 The modes are 2 and 5

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Natural number: any of the numbers 0, 1, 2, 3, 4, 5, and so on.

Negative correlation: a relationship that exists between two quantities such that one quantity increases as the other decreases; for example; the amount of fuel in the gas tank of a car decreases as the distance driven increases; on a scatter-plot a negative correlation is indicated when the dots lie approximately in a straight line that is downward and to the right.

Negative integer: any of the numbers -1, -2, -3, -4, and so on.

Negative number: any number less than zero; for example, -2, -2/5, and -4.7 are all negative numbers.

Net: a two-dimensional pattern for a solid; the solid can be rebuilt by folding the net.

Nonagon: a nine-sided polygon.

Numerator: the number above the line in a fraction; the numerator tells how many parts are being considered.

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Obtuse angle: an angle measuring more than 90 degrees and less than 180 degrees.

Obtuse triangle: a triangle with one angle greater than 90 degrees.

Octagon: an eight-sided polygon.

Octagonal prism: a prism whose bases are eight-sided polygons.

Octahedron: a solid that has eight congruent faces (triangles). It is one of the Platonic solids.

Order of operations (BEDMAS): the rules about which operation to do first when simplifying an expression; that is, operations in Brackets, then Exponents, then Division and Multiplication in the order in which they appear, then Addition and Subtraction in the order in which they appear.

Ordered pair: two numbers in brackets, separated by a comma, used to indicate the position of a point on a coordinate grid; for example, the ordered pair (3, 5) represents the point that is at coordinates x = 3 and y = 5. The first coordinate also corresponds to the independent variable while the second represents the dependent variable.

Ordinal: a number indicating position in a series; for example, first, second, third, and so on.

Origin: the point where the x-axis and the y-axis intersect.

Outcome: a possible result of an experiment or a possible answer to a survey question.

Outlier: a point (representing data) that is far from most of the other points.

Oval: a closed curve forming a symmetrical figure that is longer than it is wide.

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Parallel lines: lines in the same plane that do not intersect or lines on the Cartesian plane with the same rate of change and different initial values.

Parallelogram: a quadrilateral with both pairs of opposite sides parallel.

Pentagon: a five-sided polygon.

Pentagonal prism: a prism whose bases are five-sided polygons.

Pentagonal pyramid: a pyramid whose base is a five-sided polygon.

Perimeter: the distance around a closed figure; for example, the perimeter of a polygon is the sum of the lengths of the sides of the polygon. The perimeter of a circle is called the circumference of the circle.

Perimeter of a regular polygon: the product (times) of the number of sides and the length of one side; for example, the perimeter of a regular pentagon, with side length 7 cm, is 5 x 7 cm = 35 cm.

Period: the number or numbers that repeat an infinite number of times in a rational number (it is indicated by placing a bar above the number or numbers that repeat); for example

2.14545454545.... the period is 45

12.6666666.... the period is 6

Perpendicular: intersecting at right angles (90 degrees).

Perpendicular bisector: the line that is perpendicular to a line segment and divides the line segment into two equal parts; for example, the dotted line is the perpendicular bisector of the line segment below.

Pi (p): the ratio of the circumference of a circle to its diameter; that is, p = circumference / diameter. p is approximately equal to 3,1415926535....

Pictograph (or picture graph): a graph in which a symbol or picture represents a certain amount, and repetitions of the symbol or picture illustrate data.

Pie graph: see circle graph.

Place-value system: a number system in which the position of a digit tells its value; for example, in our decimal system the 3 in the numeral 4389 means 300.

Plane: a flat surface on which figures are drawn.

Plane geometry: the study of two-dimensional figures; that is, figures drawn or visualized on a plane.

Plane of symmetry: a plane that cuts a solid in half such that one half is congruent to the other half; for example, the diagram below shows one plane of symmetry for a cube.

Platonic solids: see regular polyhedron.

Plot: to place in the correct location on a coordinate grid.

Polygon: a closed figure that comprises line segments; for example, triangles, squares, and quadrilaterals are polygons.

Polyhedron (plural polyhedra): a solid that has only flat faces that are polygons; for example, pyramids and prisms are polyhedra; cylinders, cones and spheres are not polyhedra, they are curved solids.

Population: in data analysis, the set of all things or people being considered.

Positive correlation: a relationship that exists between two quantities in which both increase (or decrease) together; for example, the more hours a person works, the more money she is paid; on a scatter-plot a positive correlation is indicated when the dots lie approximately on a straight line that is upward and to the right.

Positive integer: any of the numbers +1, +2, +3, +4, and so on; these numbers may be written without the plus signs, that is, 1, 2, 3, 4, and so on.

Positive number: a number greater than zero; for example, 5, 3/4, 7.9 are all positive numbers.

Power: a representation of a number as the product of equal factors; for example, 64, or 4 x 4 x 4, can be expressed as the power of 4³.

Prime factor: a whole number with exactly two different factors, itself an 1; for example, 2, 3, 5, 7, 11, 13... are prime numbers; 1 is not a prime number nor is it composite.

Prism: a solid that has two congruent, parallel faces (called the bases) that are polygons and other faces that are rectangles (if the prism is right) or parallelograms (if it is oblique).

Probability: the likelihood of a particular event; if the outcomes of an experiment are equally likely, then the probability of an event is the number of outcomes favourable to the event divided by the total number of outcomes; for example, the probability of rolling a 5 when casting a die is 1 out of 6, or approximately 0.17. The probability of drawing a king out of a deck of cards with no jokers is 4 out of 52, or approximately 0.08.

Proper fraction: a fraction with its numerator less than its denominator.

Proportional: having the same ratio; for example, 1 : 5 is proportional to 2 : 10.

Pyramid: a solid whose base is a polygon and whose other faces (lateral faces) are triangles that meet at a common vertex called the apex.

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Quadrant: one of four regions into which coordinate of axes divide a plane.

Quadrilateral: a four-sided polygon; for example, a square, a rectangle, a parallelogram, a trapezoid, a rhombus, and figures with all four sides different lengths.

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Radius (plural radii): the distance from the centre of a circle to any point on the circumference; or a line segment joining the centre of a circle to any point on the circumference.

Random sample: a sample in which all members of the population have an equal chance of being selected.

Range (Ran): the difference between the greatest and least numbers (the extremes) in a set of data. For example, for the following data

10, 14, 18, 22, 35, 35, 38

Ran = 38 - 10 = 28

Rate: a certain quantity or amount of one thing considered in relation to a unit of another thing; for example, speed is a rate - 100 km traveled in 2 hours represents an average speed of 50 km per hour. Unit price is a rate - 700 g of cereal for $3.89 represents a unit price of about 0.56 cents per gram.

Ratio: a comparison of two or more quantities with the same unit; for example, in the following diagram, the ratio of green squares to yellow squares is 2 to 3 (2 : 3).

Rational numbers: any number in the set of integers, or any number that can be written as a fraction. Numbers with repeating or periodic and non-terminating decimals (the period is indicated with a bar above the number or numbers that repeat); for example, 5, -7, 0, 3/7, -5/2, 3.625, are all rational numbers.

Rectangle: a quadrilateral that has four right angles. A square is a rectangle.

Rectangular prism: a prism whose faces are rectangles.

Rectangular pyramid: a pyramid whose base is a rectangle.

Reflection or flip: a transformation that reflects a figure in a mirror line; the image is congruent to the figure but its orientation is the reverse of that of the original figure.

Regular decagon: a polygon with ten equal sides and ten equal angles.

Regular dodecagon: a polygon with twelve equal sides and twelve equal angles.

Regular figure: a closed figure that has all sides equal and all angles equal.

Regular hexagon: a polygon with six equal sides and six equal angles.

Regular octagon: a polygon with eight equal sides and eight equal angles.

Regular polygon: a polygon with equal sides and equal angles; for example, the regular triangle is an equilateral triangle, and the regular quadrilateral is a square.

Regular polyhedron (also known as the Platonic solids): a polyhedron with all faces that are congruent, regular polygons, such that the same number of faces meet at each vertex and the same number of edges meet at each vertex. The regular solids are the tetrahedron, the cube (or hexahedron), the octahedron, the dodecahedron, and the icosahedron.

Regular solid: see regular polyhedron.

Relative frequency: the number of times a particular outcome occurred divided by the total number of times the experiment was conducted.

Repeating decimal: a decimal in which one or more digits repeats endlessly. For example, the decimal for 1/3 is 0.3333333... This is written with a bar above the three. See rational numbers.

Rhombus: a parallelogram with four equal sides.

Right angle: an angle measuring 90 degrees.

Right triangle: a triangle with one 90 degree angle.

Rotation: a transformation in which a figure is turned about a fixed point. A clockwise rotation is negative and a counter-clockwise rotation is positive. In the example below, triangle 1 is mapped onto triangle 2, by a -90 degree rotation.

Rounded number: an approximation of the exact number. For example, the number 12 564 is: 12 560 when rounded to the nearest ten, 12 600 when rounded to the nearest hundred, etc...

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Sample / sampling: a representative portion of a population.

Scale: the ratio of the distance between two points on a map, model, or diagram to the actual distance between two locations.

Scale drawing: a reproduction that may be larger or smaller than the original, but is the same shape.

Scale model: a smaller version of an object that has the same proportions as the object.

Scalene triangle: a triangle with no equal sides.

Scatter-plot: a graph or data that is a set of points plotted on coordinate axes.

Scientific notation: a way to express a number as the product (times) of a number greater or equal to 1 and less than 10, and a power of 10; for example, 4700 is written as 4.7 x 10³ and 0.00065 is written as 6.5 x 10^-4.

Second-hand data: data collected by others, such as that found in books, databases, newspapers, encyclopedias, and atlases.

Sector: that part of a circle enclosed by two radii and an arc.

Semicircle: half a circle.

Shape: an attribute of a figure. For example, a three-sided figure has the shape of a triangle.

Similar: figures or solids that have the same shape but not necessarily the same size.

Slide: see translation.

Solid: a three-dimensional object with a closed, rigid surface, that contains a space. For example, a sphere, a cube or a pyramid.

Square: a rectangle with four equal sides.

Square centimetre (cm²): a metric unit used for measuring area. There are 10 000 cm² in 1 m².

Square kilometre (lm²): a metric unit used for measuring area. There are 100 hectares in 1 km².

Square metre (m²): a metric unit used for measuring area.

Square millimetre (mm²): a metric unit used for measuring area. There are 100 mm² in 1 cm².

Square of a number: the product of a number multiplied by itself. For example, 25 is the square of 5 (5 x 5 = 25).

Square pyramid: a pyramid whose base is a square.

Square units: units that measure area.

Statistics: the branch of mathematics that deals with the collection, organization, and interpretation of data.

Stem-and-leaf plot: a way to represent date. For two-digit numbers, the tens digits are the stem and the ones digits are the leaves.

Straight angle: an angle measuring 180 degrees.

Supplementary angles: two angles whose sum is 180 degrees. For example, angles RST and TSU are supplementary angles.

Surface area: the total area of all the surfaces of a solid.

Survey: questions asked of a sample of people to find out information.

Symmetrical: possessing symmetry. See line symmetry and plane of symmetry.

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T-table: a table of data

Term: of a fraction is the numerator or denominator of the fraction. Of a ratio is any of the numbers contained in the ratio.

Tetrahedron: a solid with 4 congruent faces (triangles). It is one of the Platonic solids.

Theoretical probability: the calculation of probability form an investigation of possible outcomes.

Three-dimensional: having length, width and height (or depth).

Transformation: a reproduction of a figure that results in a change in position, shape, or size of the initial figure. For example, translations, reflections, rotations, dilatations, and glide reflections are transformations.

Translation: a transformation that moves a point or a figure in a straight line to another position in the same plane; the image is congruent to the initial figure.

Trapezium: a quadrilateral with no parallel sides.

Trapezoid: a quadrilateral that has only one pair of parallel sides.

Tree diagram: a branching diagram used to show all possible outcomes of an experiment.

Triangle: a three-sided polygon.

Triangular prism: a prism whose bases are triangles.

Triangular pyramid: see tetrahedron.

Two-dimensional: having length and width, but no thickness, height or depth.

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Variable: a letter or symbol representing a quantity that can vary.

Venn diagram: a diagram in which sets and their relationships are represented by (intersecting) circles or other figures.

Vertex (plural vertices): the corner of a figure or solid.

Volume: the amount of space occupied by an object.

Volume of a rectangular prism: the product of its length, width, and height; that is

Volume = length x width x height

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X-axis: the horizontal number line on a coordinate grid or Cartesian plane.

X-coordinate: the first number of an ordered pair; it represents the distance and direction from 0 along the horizontal number line.

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Y-axis: the vertical number line on a coordinate grid or Cartesian plane.

Y-coordinate: the second number of an ordered pair; it represents the distance and direction from 0 along the vertical number line.

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