Åk 6–9
2.2 Mathematical Terminology
When you work with algebra, functions and formulas you can come in contact with new words that you haven’t heard before.  Because of this we have made a vocabulary list with words you will need to learn.  It is important that you know what all the words below mean.


Function means relation. If you call, there is a relation to how many minutes you call and how big the cost will be.

The cost is a function of the conversation’s time.


A formula is and algebraic description of a function. To calculate the perimeter of a rectangle, you can also do this with an algebraic description, a formula. The formula looks like this:

Perimeter = base · 2 + height · 2


With a graph, you can show a function in a coordinate system. If you put in a number of points from the function in the coordinate system and connect them, it is called a graph.


A constant is the opposite of a variable. A constant is a number that cannot be replaces by a value. It does not Change. If the temperature is constant, it means that it doesn’t change. It is the same the whole time.


A coordinate is a value on the number line.  In a coordinate system, a point can have two coordinates, an x-value and a y-value.

Coordinate System

Consists of two lines, axis. These are called the x-axis and the y-axis. The
-axis is horizontal and the y-axis vertical.

Linear  Function

If the graph of a function is a straight line it is called a linear function or a linear relation. If something increases or decreases equally the whole time then this can be described with a linear function.

The Origin

The point (0, 0) in the coordinate system. It is the point where the x-axis and the y-axis cross, intersect each other.

Points in the coordinate system

When we work with functions and formulas, a point is a dot in the coordinate system. The point can have one
-coordinate and one y-coordinate. (3, 4) is a point which has the value 3 on the x-axis and 4 on the y-axis.


Proportionality comes from the word proportion which means relationship.  Proportionality describes the relationship between two values.

2:4 and 6:12. Two relates to 4, as 6 relates to 12.

The graph is a straight line which goes through the origin.


”The number in front of x”.  The gradient in a linear function determines in which direction the line slopes.

Example: y = 2x + 4

This is the “number in front of x”.  The 2 determines in which direction the line will slope.


A variable represents an unknown number which can vary, in other words take on different values. In the formula for the mobile phone bill, the call time was a variable. When you know exactly how many minutes you talked, you can replace the variable with a number and calculate the cost for the call.