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maths question?!

Discussion in 'Personal' started by the apprentice, Mar 13, 2011.

  1. the apprentice

    the apprentice New commenter

    My son has been given homework set on my maths .co.uk.. and the question is
    1 - +9 = ??!! can this be right? -19-+5=.. l'm not a maths expert..l'm sure it's simple
    but finding explaining this difficult
     
  2. the apprentice

    the apprentice New commenter

    My son has been given homework set on my maths .co.uk.. and the question is
    1 - +9 = ??!! can this be right? -19-+5=.. l'm not a maths expert..l'm sure it's simple
    but finding explaining this difficult
     
  3. doomzebra

    doomzebra Occasional commenter

    It is asking you to subtract a positive number - where is the difficulty?
     
  4. lilachardy

    lilachardy Star commenter

    1 subtract positive 9 equals negative 8
    Negative 19 minus positive 5 equals negative 24.

    Use a number line to show how you count in the relative direction. Online homeworks on mymaths also have a lesson attached - if you go back to his portal page he'll have the option of the lesson or the homework. Doing the lesson first will help enormously.

    Not too sure what you're asking so I'm not too sure this is helpful!
     
  5. the apprentice

    the apprentice New commenter

    the difficulty is...he cant do it ..!!!There must be some rules to this that neither of us know!! Sorry
     
  6. the apprentice

    the apprentice New commenter

    thankyou lilac...he hasn't done a lesson on this and is getting so upset which doesn't help...think we'll look at the lesson...many thanks..long while since l did number rules etc.
     
  7. PlymouthMaid

    PlymouthMaid Occasional commenter

    I am not a mathematician but aren't they making it seem more complicated by expressing as 1 - + 9 and not just 1 - 9? Show or draw him a thermometer and explain negative numbers using that.
     
  8. lilachardy

    lilachardy Star commenter

  9. lilachardy

    lilachardy Star commenter

  10. 1 - +9 = -8

     
  11. I would agree that the number line helps.

     
  12. the apprentice

    the apprentice New commenter

    Seem to have it sorted now...we watched the lessons that can with it...just! He's completed the homework and the tears have stopped but it appears more difficult than it is..but he got so mardy and upset there was just no talking to him...thanks very much for your replies!
     
  13. Oh heck - I am sorry he got teary!
    Have you tried telling thim that he can use O as the placement? It all goes + or - from there...
    And basically, if he looks at the postitive number first, he just needs to substract the first positive number from the negative number? And then get the + and - the right way round (I may not have explained that well - I could write it down for him on a piece of paper really easily and show what I mean).
    < 0 >
    Anything behind the < is negative, anything in front of the > is positive, if you look at is as a line.
    So with the example you gave, he has to go back 9 places to the left - that brings him to - 8 (as you have the 0 as the middle).
     
  14. the apprentice

    the apprentice New commenter

    !!!! That's sounds really complicated!! He reminds me of me when l didn't understand mathematics!! l just learn the formula and don't question it!! l found out that a minus multiplied by a minus is a positive!!! that is soooo wrong to me... how can two negative numbers when made bigger by multiplying then become positive!??? it should be more negative?! L've always struggled with maths and just learn the formula and dont ask....when he checked the homework he didn't do too well, so l'm hoping the teacher will check at school and help him!!? Although on the multiplying and dividing test l got 100% !!!
     
  15. Nooooooooooo.
    Think of a line.
    --------------------------------------------0--------------------------------------------
    Anything on the left is negative, anything on the right is positive.
    So, in the case of addition and subtraction you have the 0 in the middle.
    If you look at your example, you have
    -------------------------------------------0 1---------------------
    If you subtract the 9 from the 1 you are going left, and the 0 is there.
    You are going back from the 1. To the left.
    You have one place for the 0.
    Keep counting - and where do you end?
     
  16. Perhaps easier to think of it this way
    ---------------------------------------O++++++++++++++++++++++++
     
  17. doomzebra

    doomzebra Occasional commenter

    The Left is lower than The Right
     
  18. For me it is a spiral, but that is my crazy synaesthetic head.
    For the purposes of simplicity, I think the straight number line is clearer.
     
  19. + means move forward and - means turn around

    You start facing the right
     

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