Maria Vega, age 9, of Flagstaff, Ariz., for her question:

WHAT IS A RUBLE?

A ruble, which is sometimes spelled "rouble," is the monetary unit of Russia. The ruble, like the United States dollar, is divided into 100 units. We call them "cents" in the United States. In Russia they are called kopecks.

It is difficult to determine the value of the ruble in dollars since there is no free international exchange of the Russian currency.

Russian paper money comes in values of one, three and five rubles.

Copper nickel coins are used in denominations of one ruble and also 10, 15, 20 and 50 kopecks.

Copper zinc coins are found in Russia with a value of one, two, three and five kopecks each.