Units
The unit represents the numeral 1. Measures 1cm3
Rods
The rod represents the numeral 10. Measures 1 cm x 1 cm x 10 cm
Flats
The flat represents the numeral 100. Measures 1 cm x 10 cm x 10 cm
Cubes
The cube represents the numeral 1,000. Measures 10cm3