Math Concepts
Every idea explained around something you can drag, plot or answer - with the whole working given away free.
Numbers and arithmetic
Fractions, decimals and percents
Equivalent Fractions
Two bars, one shaded length - cut into a different number of pieces each time.
Multiplying Fractions
A unit square cut both ways at once - the answer is the overlap.
Dividing Fractions
How many of these fit into that? Count them along the bar, and the flip explains itself.
Adding Fractions
Two bars re-cut into pieces of one size, then pushed together.
Algebra basics
Lines and graphs
The Coordinate Plane
Axes, origin, quadrants and ordered pairs - on a plane you can plot on.
Slope-Intercept Form
y = mx + b, with m and b on sliders so you can watch the line answer.
Point-Slope Form
One point, one slope, one line - drag either and watch the equation rewrite itself.
Function Notation
f(x) as a machine you feed: put a number in one end, read the answer off the other.
Trigonometry
Statistics and data
Correlation Coefficient
Drag the points and watch r move between -1 and 1, computed exactly.
Line of Best Fit
The one line that misses the points by the least, redrawn as you drag them.
Residuals
Observed minus predicted for every point, drawn and summed as you move them.
Categorical vs Quantitative Variables
Sort real variables into categorical and quantitative, and see why it decides the graph.
Sets and logic
