Given that 1 gram = 10 decigrams, 1 decigram = 10 centigrams, and 1 centigram = 10 milligrams, how many milligrams equal 15.8 grams?

15800. because if 1 gram is 10 decigrams than 100 centigrams are 1 gram because it's basically multiplying by ten every time you move down in measurement with a gram. I multiplied this number 15.8 by 1000 because 1 gram is 1000 times higher than a milligram.