All you have to do is count the individual grains of rice (item A), balance the amount you count with another item (item B), then uses (item B) as a reference to find (item A)'s weight
1 Kilo = 1000 Grams, and 1 grain of rice equals .028 grams. That would mean about 36 grains of rice is need to weight 1 gram. So 3600 sole grains of rice = 1 Kilo and 36000 = 10 kilos.