a)

1 000 l = 1 m³

 

b)

$1{\text{dm}}^3=1000{\text{cm}}^3$  

$0,12{\text{dm}}^3=0,12\cdot 1000{\text{cm}}^3=120{\text{cm}}^3$  

 

$120{\text{cm}}^2=0,12{\text{dm}}^2$     

 

c)

1 cm³ = 1 ml

$30\text{ml}=30{\text{cm}}^3$  

$30\text{ml}\ne 3{\text{cm}}^3$  

 

d)

1 m³ = 1000 dm³

$4,2{\text{m}}^3=4,2\cdot 1000=4200{\text{dm}}^3$   

$4,2{\text{m}}^3=4200{\text{dm}}^3$