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  1. #1
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    algebra

    State Whether Each Number Below Is Divisible By 2,3,5,9,10 Or None.
    Some Numbers May Have More Than One Divisor.

    111

    288

    52

    4805
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  2. #2
    Forum Admin topsquark's Avatar
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    Quote Originally Posted by ricky j View Post
    State Whether Each Number Below Is Divisible By 2,3,5,9,10 Or None.
    Some Numbers May Have More Than One Divisor.

    111

    288

    52

    4805
    This is a good exercise in division. Is there a specific problem you are having that we can help you with? Otherwise, just divide by each possible divisor and you have your answer. For example:
    111 is divisible only by 3

    288 is divisible by 2, 3, and 9.

    I'll let you work out the last two.

    -Dan
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  3. #3
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    Hello, Ricky!

    State whether each number below is divisible by 2,3,5,9, or 10, or None.

    (a) 111 . . (b) 288 . . (c) 52 . . (d) 4805

    What's stopping you?
    Don't you have a calculator . . . or a pencil?


    Okay, they must expect you to know some Divisibility Tests
    . . so you can simply "eyeball" the numbers.
    You already know some of them . . . right?

    . . A number is divisible by 2 if it is even (its last digit is even).
    . . A number is divisible by 3 if the sum of its digits is divisible by 3.
    . . A number is divisible by 5 if it ends in 0 or 5.
    . . A number is divisible by 9 if the sum of its digits is divisible by 9.
    . . A number is divisible by 10 if it ends in 0.


    (a) 111

    It ends in "1", an odd number . . . not divisible by 2.

    The sum of its digits is: .1 + 1 + 1 = 3, which is divisible by 3.
    . . Hence, 111 is divisible by 3.

    The last digit is not 0 or 5 . . . not divisible by 5 or 10.

    The sum of its digits is 3, which is not divisible by 9.

    . . Therefore, 111 is divisible by 3 (only).


    (b) 288

    It ends in "8", an even number . . . divisible by 2.

    The sum of its digits is 2 + 8 + 8 = 18 . . . divisible by 3 and by 9.
    . . Hence, 288 is divisible by 3 and 9.

    It does not end in 0 or 5 . . . not divisible by 5 or 10.

    . . Therefore, 288 is divisible by 2, 3, and 9.


    Got it?

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