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Math Help - different number of ways

  1. #1
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    different number of ways

    In how many ways can 12 be written as sum of two or more positive whole numbers? (changing the order of addition does not count as a different way.)

    (A) 12
    (B) 13
    (C) 14
    (D) 15
    (E) 16

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    How many different postive numbers are equal to the product two odd one-digit numbers?

    (A) 25
    (B) 15
    (C) 14
    (D) 13
    (E) 11

    Please answer these qustions with how you got that answer as well, thanks!
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  2. #2
    A riddle wrapped in an enigma
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    Quote Originally Posted by AbigailVD View Post
    In how many ways can 12 be written as sum of two or more positive whole numbers? (changing the order of addition does not count as a different way.)

    (A) 12
    (B) 13
    (C) 14
    (D) 15
    (E) 16


    Please answer these qustions with how you got that answer as well, thanks!
    Must be another restriction missing....like you can't repeat digits in your sum. In other words, 2+2+8 would not be allowed since there are two 2s.

    1+11
    2+10
    3+9
    4+8
    5+7

    1+2+9
    1+3+8
    1+4+7
    1+5+6
    2+3+7
    2+4+6
    3+4+5

    1+2+3+6
    1+2+4+5

    I get 14. No special algorithm, though. Just eyeballed it. Could've missed some, too
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  3. #3
    A riddle wrapped in an enigma
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    Quote Originally Posted by AbigailVD View Post

    How many different postive numbers are equal to the product two odd one-digit numbers?

    (A) 25
    (B) 15
    (C) 14
    (D) 13
    (E) 11

    Please answer these qustions with how you got that answer as well, thanks!
    Don't know if I fully understand what you're asking, but I'll take a stab at it.

    1 x 1
    1 x 3
    1 x 5
    1 x 7
    1 x 9

    3 x 3
    3 x 5
    3 x 7
    3 x 9

    5 x 5
    5 x 7
    5 x 9

    7 x 7
    7 x 9

    9 x 9

    That makes 15.
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