# Introductory Numbers

**Natural Numbers** - the counting numbers. Examples: 1, 2, 3, 4

**Whole Numbers** - the natural numbers and zero. Examples: 0, 1, 2, 3, 4

**Integers** - negative natural numbers, zero, and the positive natural numbers. Examples: –4, –3, –2, –1, 0, 1, 2, 3, 4

**Prime Number** - a natural number whose only factors are itself and 1.
The number 3 is a prime number because its only factors are itself and 1 (3 × 1 = 3).
Prime numbers do not include 1. Examples: 2, 3, 5, 7, 11, 13, 17, 19

**Composite Number** - a natural number that is not prime. Examples: 4, 6, 8, 9, 10, 12, 14, 15, 16, 18, 20

**Common Fraction** - part of a whole written with a numerator (the number above the vinculum line) and a denominator (the number below the vinculum line).
Examples: ^{1}⁄_{2}, ^{1}⁄_{10}, ^{2}⁄_{3}

**Decimal Fraction** - parts of a whole expressed where the parts are expressed in tenth parts. Examples: 0.5, 0.79, 0.857

**Terminating Decimal Fraction** - a decimal fraction which has a definite ending. Examples: 0.5, 0.75, 0.467

**Recurring Decimal Fraction** - a decimal fraction where one digit or a group of digits repeats. A line over the digits indicates what digits repeat. Examples: ^{1}⁄_{9} = 0.111111..., ^{1}⁄_{3} = 0.33333..., ^{2}⁄_{11} = 0.18181818...

**Index (Plural is indices)** - an exponent, a power. Used when a number is multiplied by itself. Examples: 100 = 10 squared = 10 to the index of 2 = 10^{2}

NAME | AMOUNT | NUMERALS |

Million | a thousand thousand | 1 000 000 |

Billion | a thousand million | 1 000 000 000 |

Trillion | a thousand billion | 1 000 000 000 000 |

Quadrillion | a thousand trillion | 1 000 000 000 000 000 |

Pentillion | a thousand quadrillion | 1 000 000 000 000 000 000 |

## Calculator Word Fun

Work these out on a calculator and then turn the calculator upside down.

1777 × 4

1667 × 21

877300 – 341792

8922 + 20132 + 6285

(300 + 163) × 8

(9080 + 543) × 6

Do you have friends with great calculator names like BOB and ELOISE?

Make up questions that create their names when the calculator is turned upside down.