a)1)21 ore
2)10 ore
3)9 ore 15 minute
4)4 ore 55 minute
5)1 ora 30 minute 30 secunde
6)2 ore 40 minute 40 secunde
b)1)20000000 m patrati,200000 m patrati,2000 m patrati,0.2 m patrati,0.000002 m patrati
2)5000000000 m cub,5 m cub,0.5m cub
3)8 l,0.8 l,0.08 l,0.008 l
4)70000 kg,7000 kg,0.07kg,0.00007 kg
5)180000 secunde,3600 secunde