۱۲. $72 \frac{km}{h} = x \frac{m}{s} \rightarrow 72 \frac{km}{h} \times 1 \times 1 = 72 \frac{km}{h} \times \frac{1000 m}{1 km} \times \frac{1 h}{3600 s} = \frac{72000 m}{3600 s} = 20 \frac{m}{s}$

۱۳. $3000 (dm)^3 = x (hm)^3 \rightarrow x = \frac{3000 (dm^3)}{(hm^3)} = \frac{3 \times 10^3 \times (10^{-1})^3}{1 \times (10^2)^3} = \frac{3(10^3)(10^{-3})}{1 \times 10^6} = 3 \times 10^{-6}$