A diamond weighs 5.61 ounces. How much is it worth if the going price of diamonds is 673 dollars per carat? 1 carat is equal to 200 milligrams.
The first thing, it seems to me, is to convert those ounces to grams (and then to milligrams). After that, it all should be just plain arithmetic.
http://www.google.com/search?q=convert+ounces+to+grams&oq=convert+ounces+to+grams&aqs=chrome..69i57.6393j0j7&sourceid=chrome&es_sm=119&ie=UTF-8