borrow digit
Technical term in computing and arithmetic for the digit borrowed during subtraction when a column's minuend is smaller than the subtrahend.
二進法の引き算では、借り数がよく現れる。
In binary subtraction, borrow digits appear frequently.
Compound of 借り (kari, 'borrowing') and 数 (sū, 'number'). The exact historical derivation is uncertain; the term is a modern technical coinage.