What is the ruling when a debt is stated followed by multiple nested exceptions (stating 'ten, except seven, except five, except two dirhams')?

Primary text

The statement is valid. The declarant is obligated to pay six. This is because when exceptions are chained, the subsequent exception applies to the remainder of the previous exception. Thus, 'five except two dirhams' equals three, which is excepted from seven, leaving four excepted from ten, meaning six remains as the due amount.