Units of mass, speed and area
Convert tonnes, centners and kilograms, km/h to m/s and hectares to square kilometres, and choose a sensible unit.
- Russia: grade 5
Guide
In the Russian programme (Grades 5-6) the tonne (1 t = 1000 kg) and the centner (1 c = 100 kg), the hectare (1 ha = 10 000 m2) and the square kilometre (1 km2 = 100 ha), and the speed units km/h and m/s join kg and g. Children convert between them and pick a unit that fits the situation.
To a smaller unit we multiply; to a bigger unit we divide. So 3 t 450 kg = 3 x 1000 kg + 450 kg = 3450 kg. For speed, 1 km/h = 1000 m : 3600 s, so 36 km/h = 10 m/s.
Common slips: mixing up how many kilograms are in a centner and a tonne; forgetting 3600 seconds in an hour; thinking a square kilometre holds 1000 or 10 000 hectares.