Often an overhead calculator is part of a complete package, or it may be purchased separately. Containers of all shapes and sizes may be collected or purchased. They are useful for measuring length, area, capacity, volume, mass, angles, and for studying geometric shapes. Counters are used for patterns, operations, fractions, integers, decimals, and data management. Counters may be purchased in limitless variations, at varying prices.
Some counters are transparent for overhead use.
Constructed or collected counters provide economical alternatives to purchased products. Dice may be purchased in a wide variety of formats. Common six-sided dice are readily available or easily constructed but speciality dice with more than the standard number of faces would need to be purchased. Dice are useful for probability, games, counting, various operations, and place value. The prices of dice vary considerably depending upon type.