Is it permissible to exchange one Saudi Riyal banknote for 90 halalas in coins, on the pretext of a difference in type, even though the currency belongs to the same country?

It is not permissible to sell paper currency for less than its value in metal currency if they are of the same type (e.g., Saudi currency), because it is necessary to take possession [of the exchanged items] in the same session and for them to be equal [in value]. Paper and metal currencies in our time are considered to be in the place of gold and silver. The Council of Senior Scholars in Saudi Arabia has ruled that paper money is a currency in itself, and its types multiply with the multiplicity of issuing authorities. The branches of a type follow its origins, therefore, it is not permissible to have a difference [in value] when exchanging a branch of a type with its origin.