Pre-Algebra One-Step Division Question

Discussion in 'Secondary Education' started by jamoehope, Dec 6, 2011.

  1. jamoehope

    jamoehope Companion

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    Dec 6, 2011

    The teachers taught the students how to do one-step equations with division where the problem is set up like this:
    n/2 = 5
    The students learned to multiply by 2 on both sides to remove the 2 from n and to get the answer of 10.

    I wanted to make review sheets for one-step equations. On math-drills.com at http://www.math-drills.com/algebra/algebra_missing_numbers_in_equations_variables_division_001.pdf I saw problems set up like this:
    10/n = 5

    Wouldn't the students need to do two steps to solve a problem up set like this one? Would they first multiply by n on both sides and THEN divide by 5? They can't multiply by 10 on both sides, that won't solve the problem-- but I can see the students I work with trying to multiply by 10.

    Am I missing something? Math isn't my strongest subject but I like to review math concepts to help out my students. :)
     
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  3. kme93

    kme93 Companion

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    You are absolutely correct. In order for the equation to be solved in only one step, the variable needs to be in the numerator of the fraction (on the top).
     
  4. jamoehope

    jamoehope Companion

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    Dec 6, 2011

    Thank you, so it sounds that I should avoid problems of this type until I find my students are more fluent in the basic operations for one-step equations.
     
  5. Aliceacc

    Aliceacc Multitudinous

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    Dec 7, 2011

    To be honest, I would treat that type of equation as a proportion. I would have them put the 5 over 1 and cross multiply.
     
  6. mopar

    mopar Multitudinous

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    Dec 7, 2011

    You'll find the same problem with subtraction. My students need to see both types so that they do not get in their heads that they always multiply to solve the equation.

    b-5=10 (one step)
    5-b=10 (two step)
     
  7. Good Doobie

    Good Doobie Rookie

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    Dec 22, 2011

    Well, if step one is to write it down then there are two steps.
    But if writing it down is not a step, then write 10/n = 5 up-side down as n/10 = 1/5. Now just multiply both sides by 10 to get the answer n = 2 in one step.
     
  8. Upsadaisy

    Upsadaisy Moderator

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    Dec 22, 2011

    I would just have them divide each side by 10.
     
  9. tennislove

    tennislove Rookie

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    Dec 22, 2011

    That wouldn't help, it would still be two steps.
     
  10. Aliceacc

    Aliceacc Multitudinous

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    Dec 22, 2011

    But that would give you 1/n instead of n as your answer.
     
  11. Upsadaisy

    Upsadaisy Moderator

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    Dec 22, 2011

    Yeah, I know....
     

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