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    Fractions and composite numbers problems.

    The question is: Sam wrote a two digit number. The number is a composite number and the number is also odd. Can someone explain to me how that could be possible? My son answered with the number of 89 and was wrong. Other number choices are: 23, 56, and 33. Thank you in advance.
  • #660895
    A composite number is defined as a positive integer which can be obtained by multiplying two smaller numbers other than 1. Always ignore 1 in these calculations. Even number is divisible by 2 while odd is not.

    For example 4 is a composite number because 2 x 2 = 4. It is also an even number.
    5 is a prime number. It is an odd number.
    Similarly 6 is a composite number because 2 x 3 = 6. It is an even number.
    7 is a prime number. It is an odd number.
    Also, 8 is a composite number because 2 x 4 = 8. It is an even number.
    9 is also a composite as 3 x 3 = 9. It is an odd number.
    and so on ...

    Based on above explanation -
    23 is a prime number not divisible by any smaller number (ignoring 1). It is an odd number.
    33 is a composite number because 3 x 11 = 33. It is an odd number.
    56 is a composite number because 7 x 8 = 56. It is an even number.
    89 is a prime number. It is an odd number.

    Just for information the list of composite numbers from 1 to 100 is -
    4, 6, 8, 9, 10, 12, 14, 15, 16, 18, 20, 21, 22, 24, 25, 26, 27, 28, 30, 32, 33, 34, 35, 36, 38, 39, 40, 42, 44, 45, 46, 48, 49, 50, 51, 52, 54, 55, 56, 57, 58, 60, 62, 63, 64, 65, 66, 68, 69, 70, 72, 74, 75, 76, 77, 78, 80, 81, 82, 84, 85, 86, 87, 88, 90, 91, 92, 93, 94, 95, 96, 98, 99 and 100.

    Knowledge is power.

  • #660897

    89 and 33 are the odd numbers from the choices you gave. Composite numbers are numbers that can be divided by a number other than itself. We can't divide 89 by anything other than 89. 33 on other hand can be divide by 3 and 11. So that is the correct answer.
    It is a fairly easy question.


    The stronger a light shines the darker are the shadows around it.

  • #660898
    Oh I just noticed that 23 is an odd number too but it's a prime so it's irrelevant. The answer is 33.
    The stronger a light shines the darker are the shadows around it.

  • #660922
    23, 56, and 33 are the numbers you have mentioned. Odd numbers can also be composite numbers. A composite number is a number which can be obtained by multiplying 2 numbers other than 1 and the number itself.
    21 is an odd number and it is a prime number also. 3 X 7 = 21.
    33 is an odd number and it is a prime number also 3X11 = 33.
    Like that there are some odd composite numbers also.

    drrao
    always confident


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