Convert decagram to troy grain

Gold, silver and platinum are priced per troy ounce, 31.103 g, which is about 10 % heavier than the ordinary (avoirdupois) ounce of 28.35 g. Twelve troy ounces make a troy pound of 373 g, 20 pennyweights make an ounce, and the grain, 64.8 mg, is the one unit the two systems share; it also survives in the weights of bullets and, in the US, of old-fashioned medicine doses (5 grains of aspirin is 324 mg). A standard 400 oz 'good delivery' gold bar weighs 12.4 kg.

The hectogram and the decagram are hardly ever used in English, but they are everyday shop units elsewhere. In Italy the 'etto' (hg, 100 g) is how ham and cheese are ordered at the counter: 'due etti di prosciutto' is 200 g. Sweden and Norway sell sweets and cold cuts by the 'hekto'. In Austria, Poland, the Czech Republic and Hungary the 'deka' (dag, 10 g) does the same job, so '10 deka' is 100 g; Czechs and Hungarians still write it dkg.