階かい乗じょう

noun

factorial

Mathematical term for the product of all positive integers up to a given number. Used in combinatorics and probability.

• 5の階かい乗じょうは120です。

  The factorial of 5 is 120.

• 階かい乗じょうの計けい算さんは、順じゅん列れつや組くみ合あわせでよく使つかわれる。

  Factorial calculations are often used in permutations and combinations.