I am doing the following three problems and seem to get multiply answers depending on how I do it. What is the proper tech.

Evaluate each of the following and express with the the appropriate prefix

1) $\displaystyle (430 kg)^2$

2) $\displaystyle (0.002 mg)^2$

3) $\displaystyle (230 m)^3$

Take the first one for instance. Why can't I square 430 and kg.

$\displaystyle 184900 kg^2 = 185.0 Mg^2$

Yet the text says the answer is $\displaystyle 0.185 Mg^2$

I have simiar difficulties with the others. What am I not seeing?