On the bench · not built yet

Prime Garden

Plant numbers as rectangular gardens; primes only grow in a single row. Find every shape for 36.

Nearby on the shelf

Compare animals and plants: "times as tall" vs "taller by." Sliders show the difference between additive...

Numbers go in, numbers come out; guess the rule, then build one for classmates to crack.

Zoom from one seat to a full stadium to a city; see thousands and hundred-thousands as real crowds.