Biscuit Factory explores ratio relationships in the context of gears (more info).
Biscuit factory: ratios
Biscuit factory: complex ratios
Biscuit factory: directions
Biscuit factory: create a twogear system
Biscuit factory: create a threegear system
Biscuit factory: gears and speed

Drive helps users solve proportional problems with distance and time (more info).
Drive: hard problems

Squirt helps users explore and express proportional relationships (more info).
Squirt: three containers: complex proportional relationships

NLVM: Number manipulatives
Sieve of Eratosthenes
Pascal's triangle

Learn Alberta: Exploring Number series (more info).
Exploring order of operations
Exploring powers of 10

Learn Alberta: Exploring Fractions and Percentages series (more info).
Exploring combined percentages

Learn Alberta: Exploring Measurement series (more info).
Exploring ratios and proportions
Exploring square roots
