A box contains $$2,00,000$$ medicine tablets each weighing $$20$$mg. What is the total weight of all the tablets in the box in grams and in kilograms?
$$1$$ mg $$=1000$$gm
& $$1$$ kg$$=1000$$gm
No. of tablets$$=2,00,000$$
weight of $$1$$ tablet$$=20$$mg
Total wt. of the tablets $$=$$ no. of tablets$$^{\ast}$$ wt. of $$1$$ tablet
$$=2,00,000{^{\ast}}20/1000$$ grams
$$=4000$$ grams
$$=4$$ kilograms.