We know that
[tex] \frac{ab}{cd} = \frac{a}{c} \times \frac{b}{d} [/tex]
Therefore
[tex] \frac{6\times10^{5}}{3\times10^{2}} = \frac{6}{3} \times \frac{10^{5}}{10^{2}} =2 \times 10^{5-2} = 2 \times 10^{3} = 2000[/tex]
This verifies that Camile's method is justified.