Examples · Study
Study, on a board
Not to get the answer out, but to change a number and see why it comes out that way.
A calculator is finished once it has produced the answer. CalcAnyway keeps the working on the screen as cards, so you can change a number and compare what the formula and the picture do.
What happens to the bar diagram when the numerator changes. How the area moves when the base or the height does. Which way the mean and the median go when one score is changed. Where a formula on its own is hard to read, moving the numbers and the picture together shows the relation.
Articles
Fractions, from the top
One number, two digits showing. The reduced fraction, the mixed number and the bar diagram all move at once.
Division with a remainder
"divisor × quotient + remainder" and "0 ≤ remainder < divisor". Those two conditions decide the pair.
Rounding a number off
One 34,567, four answers — depending on which place you keep and which method you use.
Area of a figure
Why the triangle is base × height ÷ 2. Drag it and the halving against the parallelogram shows.
Converting units
Multiply or divide? Keep the factor in the formula and the direction stays visible.
Reading data: a line, a histogram and the median
Push one score to an extreme and the mean moves while the median holds.
Per-unit quantities
Speed, density, population density, fuel economy — one amount divided by the amount you measure per.
Concentration of a salt solution
Divide the salt by the whole solution, not by the water. Add water and the denominator alone grows.
Balancing a lever
The heavier side does not always go down. 60 g × 20 cm balances 40 g × 30 cm.
Ohm's law, in series and in parallel
Add a resistor in parallel and the total resistance falls. Why that happens.