Referring the matter to the admitting party does not let him retract the number 100. That numeral remains part of the admission; the uncertainty concerns its subject.
For example, if he explains it as 100 dirhams plus one garment, that explanation is assessed under the rules of admissions. Simply denying that he stated 100 would contradict his earlier statement.
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What the admitting party's explanation does
Kitab al-Iqrar: Conjoined Amounts, Divine-Will Clauses, and Options
Referring the matter to the admitting party does not let him retract the number 100. That numeral remains part of the admission; the uncertainty concerns its subject.
For example, if he explains it as 100 dirhams plus one garment, that explanation is assessed under the rules of admissions. Simply denying that he stated 100 would contradict his earlier statement.