- Rational Numbers :
- Numbers that can be represented/written in the form
**p / q**where**p and q are integers**and**q is not 0** - Any integer or whole number can also be written in the format p/q. e.g. 4 can be written as 8/2 or 4/1 or 12/3 … Similarly, -5 can be written as 10/-2 or -25/5 or -5/1 …
- The Sum of two rational numbers is a rational number which means “Rational Numbers are closed under addition”
- The Difference between two rational numbers is a rational number which means
**“Rational Numbers are closed under subtraction”** - The product of two rational numbers is a rational number which means
**“Rational Numbers are closed under division”** - The division of two rational numbers is not a rational number which means
**“Rational Numbers are NOT closed under division”**.**a, a / 0 is not defined**.

- Numbers that can be represented/written in the form

Numbers | ||||

Addition | Subtraction | Multiplication | Division | |

Rational Numbers | Yes | Yes | No | |

Integers | Yes | No | ||

Whole Numbers | Yes | |||

Natural Numbers | No |

$latex i\hbar\frac{\partial}{\partial t}\left|\Psi(t)\right>=H\left|\Psi(t)\right>$