### Monday, 25 January 2010

## Prime No.s (2)

**:**

*Textbook p9 #25*The Prime factorisation of a number is 2^4 X 3^5 X 7^2 X 11.

Write down 3 factors of the number that are greater than 100.

2x7x11=154

3x5x7=105

7x3x11=231

*:*

**Textbook p9 #26**The Prime factorisation of two numbers are 2 X 3^2 X 7^3 X 13 and 3 X 7^2 X 13^3 X 17 .

Write down 3 common factors of the numbers. 3,7,13

## Prime No.s

Question:

A mathematician proposed that "Every even number greater than 2 can be expressed as a sum of prime numbers."

Do you agree? Why?

Ans:

Yes I agree.

Because 6=2+2+2, 8=5+3, 10= 5+5,10=3+3+2+2, 12=3+3+3+3, 12=3+3+2+2+2, etc.......

### Saturday, 16 January 2010

## 12 January: Numbers as a Language

We can use roman numerals, i have a programme (excel from my pri sch teacher) which can convert hindu-araibic to roman numerals and back, but it only works for Microsoft OS.

For more info you can go to http://en.wikipedia.org/wiki/Roman_numerals

2010 in roman numerals is MMX. ^.^

Symbol | Value |
---|---|

I | 1 (one) (unus) |

V | 5 (five) (quinque) |

X | 10 (ten) (decem) |

L | 50 (fifty) (quinquaginta) |

C | 100 (one hundred) (centum) |

D | 500 (five hundred) (quingenti) |

M | 1000 (one thousand) (mille) |

Symbol | Value |
---|---|

V or (V) | five thousand |

X or (X) | ten thousand |

L or (L) | fifty thousand |

C or (C) | one hundred thousand |

D or (D) | five hundred thousand |

M or (M) | one million |

×1 | ×2 | ×3 | ×4 | ×5 | ×6 | ×7 | ×8 | ×9 | |
---|---|---|---|---|---|---|---|---|---|

Ones | I | II | III | IV | V | VI | VII | VIII | IX |

Tens | X | XX | XXX | XL | L | LX | LXX | LXXX | XC |

Hundreds | C | CC | CCC | CD | D | DC | DCC | DCCC | CM |

Thousands | M | MM | MMM | IV | V | VI | VII | VIII | IX |

Ten thousands | X | XX | XXX | XL | L | LX | LXX | LXXX | XC |

Hundred thousands | C | CC | CCC | CD | D | DC | DCC | DCCC | CM |

For more info you can go to http://en.wikipedia.org/wiki/Roman_numerals

2010 in roman numerals is MMX. ^.^

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