# Math*

Here are some useful built-in words for common mathematical functions. You may skip this section, but use it as a reference later.

Word | Action |
---|---|

FLOOR |
Displays the floor of a number, which is the closest integer lower than the given number. |

CEIL |
Displays the ceiling of a number, which is the closest integer higher than the given number. |

ROUND |
Rounds off a real. |

MIN |
Minimum of a two numbers. |

MAX |
Maximum of a two numbers. |

^ |
Exponentiation 2 3 ^becomes 8 |

TAN |
Usual trigonometric functions. |

ATAN2 |
The special arctangent, very useful for computing directions from vectors. A definition may be found here: Wikipedia: Atan2 |

#e |
Constant values of e and π. |

EXP |
Natural exponentiation and natural logarithms. |

LOG10 |
Logarithms base 10. |

TO-DEG |
Converts angles to degrees or radians. |

MOD |
Integer modulus and real modulus. Use FMOD if either operand is a real number. |

ABS |
The absolute value. |

## Logical Operators

Word | Action |
---|---|

TRUE |
Puts the logical value trueon the stack. |

FALSE |
Puts the logical value falseon the stack. |

OR |
Logical or. For example, true 1 2 = ORbecomes true. |

AND |
Logical and. For example, true 1 2 = ANDbecomes false. |

## Quiz

### Question 1

Use words you learnt to find the truncation part of a number. For example,5.25should display.your code here

5.0.

### Question 2

There is a built-in wordDUPthat duplicates the top of the stack. For example,

5.25 DUPends up with

5.25 5.25on the stack.

Use

DUPand words you learnt to find the fractional part of a number. For example,

5.25should display.your code here

0.25.

### Question 3

Do your solutions work for negative numbers?5.25 abs floor . 5.0 ok 5.25 abs dup floor -. . 0.25 ok -5.25 abs floor . 5.0 ok -5.25 abs dup floor -. . 0.25 ok