関連ワード:  what is the set of counting numbers    what is the set of counting numbers called    what is the set of whole numbers    what is the set of whole numbers and their opposites    what is the set of whole numbers less than 20    what is the set of whole numbers and their opposites called    what is the set of whole numbers closed under    what is the set of whole numbers less than 10    what is the set of whole numbers called    which is the set of whole numbers between ten and fifteen