整數：integer，whole number 因子：factor or divisor
If x and y are integers and x0,x is a divisor of y provided that y=xn for some integer n. In this case y is also said to be divisible by x or to be a multiple of x. For example, 7 is a divisor or factor of 28 since 28=74, but 8 is not a divisor of 28 since there is no integer n such that 28=sible adj.可以被整除的 multiple n.倍數
2.商和餘數：quotients and remainders
餘數和商都可以爲0
3.奇數和偶數：odd and even integers
奇數和偶數都可以是負數;零一定是偶數
4.質數和合數：prime numbers and composite numbers
A prime number is a positive integer that has exactly two different positive divisors，1 and itself. For example, 2,3,5,7,11, and 13 are prime numbers, but 15 is not, since 15 has four different positive divisors, 1, 3, 5, and 15. The number 1 is not a prime number, since it has only one positive divisor. Every integer greater than 1 is either prime or can be uniquely expressed as a product of prime factors. For example, 14= , 81= , and 484= .