How to Calculate a Percentage: 3 Easy Methods
Learn three simple ways to calculate a percentage of a number, find what percent one number is of another, and work out percentage change.
Maths guides
Step-by-step guides, worked examples and study tips.
Binary and Hexadecimal Explained: Converting Number Bases
How place value works in binary and hexadecimal, and how to convert between decimal, binary and hex step by step.
Box Plots and Quartiles: Five-Number Summary and Outliers
How to find quartiles and the interquartile range, draw a box-and-whisker plot, and spot outliers with the 1.5 × IQR rule.
Completing the Square and Vertex Form, Step by Step
Learn how to complete the square to write a quadratic in vertex form a(x − h)² + k, find the vertex, and see why it matters for graphs.
Complex Numbers for Beginners: i, Arithmetic and the Argand Diagram
What i = √−1 means, how to add, multiply and divide complex numbers, and how modulus, argument and the Argand diagram work.
Confidence Intervals Explained (Without the Jargon)
What a 95% confidence interval really means, how to calculate one from a sample mean, and how sample size changes the margin of error.
Exponential Growth and Decay: Formula, Doubling Time and Half-Life
Understand exponential growth and decay, use A = A₀(1 + r)ᵗ, and find doubling times and half-lives with logarithms. Worked examples.
Graphing Sine and Cosine: Amplitude, Period and Phase Shift
Learn how A, B, C and D change the graph of y = A sin(Bx + C) + D, with worked examples for amplitude, period, phase shift and midline.
How Loan Repayments Are Calculated (EMI and Mortgages)
How the monthly payment on a loan or mortgage is worked out, why early payments are mostly interest, and how rate and term change the total.
How to Factor Polynomials: A Practical Checklist
A step-by-step checklist for factoring polynomials: common factors, differences of squares, quadratics, grouping and the factor theorem.
How to Find the Determinant of a Matrix
Calculate 2×2 and 3×3 determinants with ad − bc and cofactor expansion, learn what a zero determinant means, and see it as an area.