Distinguish between money value of money and commodity value of money.
Money value of money refers to the value which is inscribed on a coin or writien on a paper note. With a five hundred rupee note, you can buy goods and services worth five hundred rupees in the market.
Commodity value of money refers to value of the commodity (like metal) that the money is made of. Thus, if coins are made of gold or silver (as was the practice in old days), commodity value of money refers to the market value of the gold or silver contained in the coin.