irrational number 无理数
integer 整数
fraction 分数
denominator 分母
numerator 分子
decimal 小数
1. 0.5 is a rational number because it can be written as 1/2.
0.5 是一个有理数，因为它可以用 1/2 来表示。
2. Every integer is a rational number.
每个整数都是有理数。
3. Is the square root of 2 a rational number?
平方根 2 是一个有理数吗？
A: Is the number 0.75 a rational number?
A：0.75 这个数是有理数吗？
B: Yes, it can be expressed as 3/4.
B：是的，它可以表示为 3/4。
1) A number that can be expressed as a fraction p/q where p and q are integers and q is not zero.
2) Any number that can be written as the ratio of two integers.
3) A number with a decimal expansion that either terminates or repeats.
1. 有理数
e.g.
$\frac{2}{3}$ is a rational number.
$\frac{2}{3}$ 是一个有理数。
noun phrase
1. A number that can be expressed as a fraction of two integers, where the denominator is not zero.