Simplify the following text for a Grade 8 native English-speaking person.
Original: Coins were introduced in 1937 in denominations of 1 , 5 , 10 , 25 centavos and Â 1\/2 pesos with small numbers of 1 peso coins first minted in 1939 .
Simplified: Coins were introduced in 1937 in denominations of 1 , 5 , 10 , 25 and 50 centavos .