We won't do your homework for you but we will be glad to check your efforts and offer help and suggestions. A hint however: hg is hectograms -- look that up and do the conversion.

What I want to know is, WOW! Where do you get a balance that will weigh over a million kilograms to the nearest milligram?!

Check to see if you are missing a decimal point in your question. But it is a LOT of significant figures in any case!!