Simplify the following text for a Grade 4 native English-speaking person.
Original: There are 5 , 10 , 25 , 50 and 100 halala coins ; and 1 , 5 , 10 , 20 , 50 , 100 , and 500 riyal banknotes .
Simplified: Cupro-nickel 5 , 10 , 25 and 50 halala followed in 1972 .