Gears, sets offer 40-, 30- and 20-tooth gears with 3/16in bore to accommodate the most popular dowel size, and a 12-tooth gear with a push-fit to 2 mm motor shafts. Three inserts are provided on each sprue, allowing the 3/16in bore to reduce to 3 mm
Number, Measurement and Space, module establishes equivalence of sets by a one-to-one exchange of objects. Eg Upsetting equivalance (destroying conservation of numbers) by adding one object to a set, or taking one away, helps introduce vocabulary for comparing quantity