Is it necessary to return the same banknotes when restoring a trust, or is it sufficient to return the same amount?

Paper currency is not intended for its own sake, it has equal value, and returning its equivalent is sufficient. A debt is cleared by giving papers whose value we name, and it is not a condition to give the exact papers that were received. For example, if someone has ten hundred-unit notes, he can pay two five-hundred-unit notes. Dinars and dirhams are not specified by their physical form, and circulating currency is similar.