They are real numbers that cannot be expressed as a ratio of two integers.
An irrational number is one that cannot be expressed as a ratio of two integers.
Any real number which cannot be expressed as a ratio of two integers is an irrational number.
Any number that can be expressed as the ratio of two integers is a rational number.
A rational number is a real number that can be expressed as a ratio of two integers; an irrational number cannot be so expressed.
Any number that cannot be expressed as the quotient of two integers.
An irrational number.
When it is a real number that cannot be expressed as a ratio of two integers.
Any number which cannot be expressed as a ratio of two integers.
An irrational number is one which cannot be expressed as a ratio of two integers.
They are real numbers that cannot be expressed as a ratio of two integers.
An irrational number is one that cannot be expressed as a ratio of two integers.
Any real number which cannot be expressed as a ratio of two integers is an irrational number.
Any number that can be expressed as the ratio of two integers is a rational number.
A rational number is a real number that can be expressed as a ratio of two integers; an irrational number cannot be so expressed.
An irrational number is a real number that cannot be expressed as a ratio of two integers.
It is not always easy to tell if a number is irrational. If a number can be expressed as a ratio of two integers, then it is rational. If not, it is irrational. So the expression is in the negation: a number than cannot be expressed as a ratio of two integers.