Percent
Where percentages show up in real life
4 live exhibits. Each one already works. Change a number and see what happens.
Open as board Play with these together. Solving one grows related exhibits.
PercentSale price and tax: what you really pay
30% off, then tax on top. Percent math decides the number at the register.
PercentPercent change: up 50%, then down 50%, and you’ve lost money
A percent is always “of something.” Change the something and the same percent means a different amount.
Linear EquationsVoltage drop: what the wire takes before the load gets it
Current times wire resistance is voltage you never get to use.
StatisticsPoll margin of error: why about 1,000 people gives ±3%
The margin shrinks with the square root of the sample. Four times the people only halves it.