Blog
Maths from everyday life, with charts you can explore yourself.
8 posts
Powers and roots · 8 min read
Powers and roots: the rules
What a power is, the four rules, negative exponents and how to simplify √72. With figures you can slide and count.
Solving equations · 8 min read
Solving equations: balance and graph
Solve equations with the balance method, through brackets and fractions, with two crossing lines and with x², from factorising to the quadratic formula.
Pythagoras' theorem · 10 min read
Pythagoras in the plane and in space
Why a² + b² = c² is true, how to work out a side, how to check for a right angle, and how to find distances and space diagonals.
Linear functions · 8 min read
Linear functions: the straight line y = ax + b
What a and b do in y = ax + b, and how to find the line through two points.
Quadratic functions and parabolas · 9 min read
Parabolas: vertex, roots and the quadratic formula
Slide a, b and c and drag the vertex until you see where a parabola turns and crosses the x-axis.
Intervals · 7 min read
Intervals on the number line
Solve inequalities and write them as intervals: open and closed ends, infinity, and/or, and quadratic inequalities.
Trigonometry on the unit circle · 9 min read
Sine and cosine on the unit circle
Turn a point around a circle of radius 1 and see why sin 140° = sin 40° and why sin α = 0.5 has two answers.
Lines and circles · 8 min read
Lines and circles: the equation of a circle
From Pythagoras to (x − a)² + (y − b)² = r². Read off the centre and radius, complete the square, and find where a line meets a circle.