Math

Place value

Place value is the value of a digit based on its position in a number, such as the 3 in 4,321 representing 300.

Fraction to percentage

$\frac{3}{4} \times 100 = 75\%$ (to convert a fraction to a percentage, multiply by 100)

Frequency

The number of times a value occurs in a data set.

Difference of two squares

$$a^2 - b^2 = (a+b)(a-b)$$

Linear equation (straight-line form)

An equation of the form $y = mx + c$, where $m$ is the gradient and $c$ is the y-intercept.

Angle sum of a triangle

The sum of all the interior angles of a triangle is $180^\circ$.

Area of a circle

$A = \pi r^2$, where $r$ is the radius of the circle.

Pythagoras' theorem

$a^2 + b^2 = c^2$, where $c$ is the hypotenuse of a right-angled triangle.

Mode

The number of times a value occurs in a data set.

Mean (average)

$$\text{Mode} = \text{the most frequently occurring value}$$

Mean (average)

$\bar{x} = \frac{\sum x}{n}$, where $\sum x$ is the sum of all values and $n$ is the number of values.