The file was prepared as a part of the Comenius project Why Maths

2. A whole number that has more than two factors
6 is a composite number because it has three factors:
1, 3, and 6
A number greater than 1 that has exactly two different
factors, 1 and itself
5 is a prime number, as its only factors are 1 and 5.
Any one of the ten numerals: 0, 1, 2, 3, 4, 5, 6, 7, 8, or 9.
A whole number that is divisible by 2; a number that has
0, 2, 4, 6, or 8 in the ones place
A number that is not divisible by 2; a number that has 1, 3, 5,
7, or 9 in the ones place
A number or expression that is multiplied by another to yield
a product
All the factors of 6 are: 1, 2, 3, and 6

3. A number placed to the top right of another number (base) to
indicate the number of times the base is multiplied by itself
4
3
A method of writing or displaying numbers in terms of
a decimal number between 1 and 10 multiplied by a power
of 10
The scientific notation of the number 5,300,000 is
5.3 ∙ 106
A number (factor) that, when multiplied by itself, produces the
given square
2
3
2

4. The set of counting numbers. Natural numbers include
1, 2, 3, 4, . . . .
The set of counting numbers plus 0 {0, 1, 2, 3, . . . }.
The set of numbers consisting of the whole numbers: 1, 2, 3, 4, . . .,
their opposites -1, -2, -3, - 4, . . ., and 0.
Any number that can be expressed as a fraction in the
form a/b where a and b are integers and b ≠ 0. All
rational numbers can be expressed as a terminating or
repeating decimal.
A real number that cannot be represented as an exact
ratio of two integers; the decimal form of the number
never terminates and never repeats
The set of numbers that includes all rational and
irrational numbers.

5. 2
 9
2 0
83
7
4

5
1.23456789...
0.7
5
8

6. subtraction
+
–
multiplication

division

=
addition
equal
Any of the numbers in a designated sum of two or more numbers
The result of adding two or more quantities
18  13  24  55

7. 35  13  22
Factors are numbers you can multiply together to get another number
15  4  60

8. A number to be divided by another number (divisor)
The number by which the dividend is divided
54 : 9  6
Remainder is the amount left over after division when one divisor
does not divide the dividend exactly
14 : 3  4 r 2
A method of approximating a number to its nearest place value

9. 5
8
Numerator
Denominator
A proper fraction is a fraction where the numerator (the top
number) is less than the denominator (the bottom
number)
5
8
smaller
larger
An improper fraction is a fraction where the numerator
(the top number) is greater than or equal to the
denominator (the bottom number).
8
5
larger (or equal)
smaller (or equal)

10. also called mixed numbers
A mixed fraction is a whole number and a proper fraction combined.
3
2
4
Fractions that represent the same amount.
When we multiply or divide both the top
and bottom by the same number, the
fraction keeps it's value
1 2 3
 
2 4 6
Common denominators for ½ and 2/5 and are 10, 20, 30, . . .

11. A fractional number written in base ten form
0.56 is a decimal number
4.7 is a mixed decimal number
452.76
A decimal in which one .or more digits repeat infinitely
e.g., 0.777777 . . . , or 0.7
Percent means parts per 100. The symbol is %

12. The addends of an algebraic expression involving constant(s)
and at least one variable.
Examples
3xy contains one algebraic term: 3xy
5x2 — 3y contains two algebraic terms: 5x2 and —3y
4x  5  7
In Algebra a term is either:
* a single number, or
* a variable, or
* numbers and variables multiplied together.
A polynomial with just one term.
Example: 5x2
A polynomial is a monomial or a sum or difference of two or
more monomials.
Example: 3x + 8, 4a2 + 2a – 5, 3x2 – 12xy + 15y2

13. A constant that multiplies a variable
In 3x + 4y = 14, 3 is the coefficient of x and 4 is the coefficient of y.
A symbol used to represent a number in an expression
In 2n + 3 the variable is n
3x  4  5
A mathematical sentence stating that two expressions are equal.
3x  4  5
x  5x  6  0
2
 2 x  4  10

14. A particular side or face of a geometric figure.
Lying on the same straight line.
In the illustration below, A, B, and C are collinear

15. Two figures that have the same shape and size.
Two angles are congruent if they have the same measure
Triangles are congruent when they have
exactly the same three sides and exactly
the same three angles.
The perpendicular distance from a vertex to the line containing the
opposite side of a plane figure; the length of a perpendicular from the
vertex to the plane containing the base of a pyramid or cone

16. The side of a right triangle opposite the right angle; the longest
side of a right triangle.
One of the two sides that form the right angle of a
right triangle; the sides that are not the hypotenuse.
A part of a line between two endpoints along the line.
A line segment is named by the endpoints.
A
B

17. A line that divides a figure into two congruent parts so
that they can be matched by folding the shape in half.
Line AB and line CD are parallel
The total distance around a closed figure.
Lines, faces, or edges that intersect at right angles (90°) to
each other.

18. A line, segment, or ray that meets a line segment
at a right angle and divides the line segment into
two equal pieces.
A
B
A set of points forming a flat surface that extends without end in all
directions.
Part of a line that has one endpoint and extends infinitely in one
direction.

19. A line segment joining two adjacent vertices of a polygon.
AB is a side of ΔABC
The common endpoint of two sides of a polygon.
The common endpoint of two rays that form an angle.
All points on a flat surface that are the same distance from a fixed point.
The fixed point is called the centre of the circle.
The distance around (perimeter of) a circle, calculated by
multiplying the length of the diameter (d) of the circle by pi
(π)

20. A line segment of a circle passing through the centre of the circle.
A line segment that extends from the centre of a circle to any point
on the circle; equal to half the diameter.
A line segment joining two points on a cirlce.
A straight line that touches the cirlce at one point.
A

21. A geometric figure formed by two rays or line segments (also called
arms) with a common endpoint (called a vertex).
An angle whose measure is greater than 0° and less than 90°.
A 90° angle; an angle formed by two perpendicular lines.
An angle whose measure is greater than 90° and less than 180°.
An angle with a measure of 180°.
An angle whose measure is greater than 180° and less than 360°.

23. Two angles are supplementary if they add up to 180
degrees.
Two angles are complementary if they add up to 90
degrees (a right angle).

24. β1 γ1
α1
δ1
β2 γ2
α2
α1 and α2
β1 and β2
γ1 and γ2
δ1 and δ2
δ2
γ1 and α2
β1 and δ2
α1 and γ2
δ1 and β2

25. A line segment or ray that divides an angle into two congruent
angles.
An angle on the inside of a polygon formed by two adjacent
sides of the polygon.
An angle between any side of a shape, and a line extended from the
next side.

26. An angle whose vertex is at the centre of a circle and whose sides
contain radii of the circle.
An angle whose vertex is at the centre of a circle and whose
sides contain radii of the circle.

27. A triangle in which all three angles are acute.
A triangle with one right angle.
A triangle containing one obtuse angle.

28. A triangle with three congruent sides and three
congruent angles.
A triangle with at least two congruent sides and two
congruent angles.
A triangle with no congruent sides and no congruent angles.

29. Polygons with four sides and four angles.
A quadrilateral with two pairs of parallel sides.
A quadrilateral with four right angles; a parallelogram with a right
angle.
A parallelogram with all four sides congruent.

30. A rectangle with all sides congruent (equal in measure); a rhombus with
a right angle.
A quadrilateral with at least one pair of parallel sides.

31. A closed plane figure formed by three or more line segments.
A polygon with ten sides.
A polygon with seven sides and seven angles.
A polygon with six sides and six angles.

32. A polygon with nine sides and nine angles.
A polygon with eight sides and eight angles.
A polygon with five sides and five angles.

33. A polygon in which all sides and all angles are congruent
(equal).
A line segment connecting two non-adjacent vertices of a polygon
convex polygon
concave polygon

34. The plane formed by a horizontal axis and a vertical axis, often labelled the
x-axis and y-axis respectively; contains quadrants 1 to 4 (the quadrants are
often labelled using Roman numerals I to IV).
An ordered pair of numbers that
identifies, or is used to locate, a point on
a coordinate plane, written as (x, y).
The point on the coordinate plane where
the x- and y-axes intersect; has
coordinates (0, 0).
One of four sections of a coordinate grid
separated by horizontal and vertical axes.

35. Solid
A regular 3-D object with 6 congruent square faces, 12 congruent
edges, and 8 vertices.

36. A 3-D figure that is bounded by four or more polygonal faces.
A polyhedron whose base is a polygon
and whose lateral faces are triangles that
share a common vertex.
A 3-D figure (solid) that has two congruent and parallel faces that are
polygons (the bases); the remaining faces are parallelograms.
A prism with a triangular base.
A prism whose six faces are rectangles; a prism with
a rectangular base

38. The sum of the areas of the faces or curved surface of a 3-D
object.
The amount of 3-dimensional space an object occupies.
A line segment where two faces of a 3-D figure intersect.
A flat surface of a solid
The 2-D set of polygons of which a 3-D object
is composed.

39. A graph that uses horizontal or vertical
bars to display data.
A graph in which the data is represented by
sectors (parts) of a circle (whole); the total of
all the sectors should be 100% of the data.
Each section of the circle represents a part or
percentage of the whole.

40. A graph that uses pairs of bars to compare and
show the relationship between data.
A bar graph that displays the frequency of data that has been
organized into equal intervals; the intervals cover all possible
values of data; therefore, there are no spaces between the bars of
the graph; the horizontal axis is divided into continuous equal
intervals.

41. A graph that uses line segments to show changes in
data; the data usually represents trends, relationships,
or a quantity changing over time.
A measure of central tendency; the quotient obtained when the sum
of the numbers in a set is divided by the number of addends; the
arithmetic average.
Example: Four tests results: 15, 18, 22, 20 The sum is: 75
Divide 75 by 4: 18.75
The mean (average) is 18.75
The middle value in an ordered list. If there is no middle value, the
median is the average of the two middle values.
Example: Scores: 2, 2, 4, 6, 8, 9, 10 Median = 6
The number or members of a data set that occur(s) most frequently
in the set of data.
Example: In scores: 2, 2, 2, 4, 6, 6, 6, 6, 8, 9, 10 Mode = 6

42. The difference between the greatest and the least values
in a set of numbers.
Example:
Find the of the following data set: 9, 4, 17, 5, 7, 10, 13
The lowest number is 4. The highest number is 17. Range = 17 - 4 = 13
To ask either written or verbal questions for the purpose of acquiring
information/data.
The results of a question or questions answered by a group of
people.
An event that has a 100% chance of occurring
Example:
A die numbered 1-6 is rolled.
It is certain that the die will land on a number 1 - 6.
An event that has a 0% chance of occurring
Example:
Rolling the number 7 when tossing a six-sided number cube
labelled 1 to 6