NB Grade 7 Math key terms

A whole number that can be positive, negative, or zero, with no fraction or decimal part. Examples are −7, 0, 12, and 305.

Two numbers that are the same distance from zero on a number line but on different sides, such as 5 and −5. Their sum is always zero.

The distance a number is from zero on a number line, written with two vertical bars. It is never negative, so |−8| = 8 and |8| = 8.

The agreed sequence for calculating an expression: first brackets, then exponents, then multiply or divide left to right, then add or subtract left to right.

A number produced by multiplying an integer by itself, such as 1, 4, 9, 16, 25, and 36. Its square root is a whole number.

A number that, when multiplied by itself, gives the original value. For example, 6 is the square root of 36 because 6 × 6 = 36.

A comparison of two quantities by division, often written with a colon or as a fraction. For example, 3 : 5 compares three parts to five parts.

A ratio that compares two quantities measured in different units, such as kilometres per hour, dollars per kilogram, or words per minute.

A rate in which the second quantity is one unit, such as 60 km per 1 hour or $2.50 per 1 kilogram. It makes comparisons easier.

An equation stating that two ratios are equal, such as 3/4 = 9/12. Cross-multiplying can test whether a proportion is true.

A ratio that compares a number to 100. Fifty percent means 50 out of every 100, which is the same as the decimal 0.5.

A decimal whose digits stop after a certain place, such as 0.75 or 3.125. It can be written as a fraction with a denominator of 10, 100, and so on.

A decimal in which one or more digits repeat forever, such as 0.333… or 0.181818… A bar over the repeating digits shows the pattern.

A letter or symbol used to stand for an unknown or changing number. In the expression 4n + 3, the variable n can take different values.

A combination of numbers, variables, and operations with no equals sign, such as 5x − 7 or 2(a + 3). It can be simplified or evaluated.

A mathematical statement saying two expressions have the same value, joined by an equals sign. For example, 3x + 4 = 19 is true only for a certain x.

The number that multiplies a variable in a term. In 7y the coefficient is 7, and in −3ab the coefficient is −3.

A relationship between two quantities whose graph is a straight line. The pattern changes by a constant amount each time, as in y = 2x + 1.

A description that tells how each term in a sequence is built from the one before it, or how to find any term directly from its position number.

An operation that undoes another one. Addition and subtraction are inverses, and so are multiplication and division. They are used to solve equations.

The distance from the centre of a circle to any point on the circle. It is half the diameter and is used to find circumference and area.

The distance across a circle through its centre. It equals twice the radius and divides the circle into two equal halves.

The distance all the way around a circle. It can be calculated with C = πd or C = 2πr, using 3.14 as an approximation for π.

The amount of flat surface covered by a shape, measured in square units such as square centimetres. Formulas differ by shape, for example length × width for rectangles.

The amount of space a 3-D object occupies, measured in cubic units. For a rectangular prism it equals length × width × height.

The total area of all the faces or curved surfaces of a 3-D object, measured in square units. It is like the area of the object's unfolded net.

A flat pattern that folds up to make a 3-D object. A net shows every face, so it helps you count faces and calculate surface area.

A change in a figure's position, orientation, or size on a coordinate plane. Slides, flips, turns, and enlargements are all transformations.

A slide that moves every point of a figure the same distance in the same direction. The shape stays the same size and is not turned or flipped.

A flip that creates a mirror image of a figure across a line. Each point and its image are the same distance from that line.

A turn of a figure about a fixed point, called the centre of rotation, by a given angle such as 90° clockwise. Size and shape do not change.

Two numbers written in the order (x, y) that locate a point on a coordinate plane. The first number is horizontal, the second is vertical.

The point (0, 0) where the horizontal and vertical axes of a coordinate plane cross. Distances are often measured from this point.

The average of a data set, found by adding all the values and dividing by how many values there are. It is affected by very large or small values.

The middle value of a data set arranged in order. If there is an even number of values, the median is the mean of the two middle values.

The value that appears most often in a data set. A set can have one mode, several modes, or no mode at all.

The difference between the greatest and least values in a data set. It describes how spread out the data are.

A value that is much smaller or much larger than the rest of the data. Outliers can pull the mean away from the median.

A number from 0 to 1 that describes how likely an event is. Zero means impossible, 1 means certain, and 0.5 means an even chance.

The set of all possible outcomes of an experiment. For one roll of a number cube, the sample space is 1, 2, 3, 4, 5, and 6.