Remember K H D | d c m (kilo, hecto, deka, (liter, meter, gram), deci, centi, milli). These are the denominations you need to list when converting metric units. Kilograms are three places to the left of grams. So you have to move the decimal place three times to the left (same as dividing by 1000). You will get 15 g = .015 kg.