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Math Help - number theory

  1. #1
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    number theory

    in base 5 devise test for:

    divisibility by 2,4,5
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  2. #2
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    Hello, teeplkyl!

    In base-5, devise tests for divisibility by 2, 4, 5

    Divisible by 2

    If there is an even number of odd digits, the number is divisible by 2.

    Examples: . 2143_5 is even (298). . 4032_5 is odd (517)


    Divisible by 4

    Add the digits.
    If the sum is divisible by 4, the number is divisible by 4.

    Example: . 12,032_5\quad\Rightarrow\quad 1+2+0+3+2 \:=\:8
    . . . . . . . .Since 8 is divisible by 4, 12,032_5 is divisible by 4 (872).


    Divisible by 5

    A number is divisible by 5 if it ends in zero (0).

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  3. #3
    Banned
    Joined
    Jan 2008
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    Study Number Theory

    It is very difficult to study Number Theory topic. Not many good reference textbooks to study Number Theory.

    I use A Friendly Introduction to Number Theory, 3rd Edition to study. This is good reference textbook.

    Do you have any other good Number Theory related textbooks recommend?

    Regards,

    Andy
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