Chap 2: Real Numbers - Spot the Common Mistakes (I)

Revision Exercise 2 (p52 of Textbook) No. 7(a)

24 comments:

  1. It should be 48-(-40)
    =48+40
    =88

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  2. The correct working should be :
    (-16)x(-3)-(-8)x5
    =48-(-40)
    =88

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  3. (-16)x(-3)-(-8)x5
    =48-(-40)
    =48+40
    =88
    The negative sign for '(-8)' disappeared.

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  4. (-8)x5= to -40 not 40.
    so the equation should be: 48 - (-40) = 88

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  5. It should be negative 40.
    (-16)x(-3)-(-8)x5
    =48-(-40)
    =88

    ReplyDelete
  6. it should be:
    (-16)*(-3)-(-8)*5
    =48-(-40)
    =88
    and not:
    (-16)*(-3)-(-8)*5
    =48-40
    =8

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  7. The second part of the equation. (-8)*5 is equal to (-40). When you remove the brackets the negative and the negative while turn into positive. Thus it becomes 48+40=88

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  8. (-46) x (-3) - (-8) x 5
    =48-(-40)
    =48+40
    =88

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  9. The working is wrong.
    Instead of ...
    (-16)x(-3)-(-8)x5
    =48-40
    =8(Ans)

    It should be...
    (-16)x(-3)-(-8)x5
    =48-(-40)
    =88(Ans)

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  10. For the second number sentence, it should be 48+40 instead of 48-40. Thus, the answer should be 88.

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  11. (16) x (-3) - (-8) x 5
    = 48- (-40)
    = 88 ( Answer )

    It is 48 subtract (-8) x 5 and not
    48 subtract 8 x 5
    Therefore it is 48- (-40) instead of 48-40 and the answer is 88 instead of 8.

    -Christopher Nah

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  12. The equation should be expressed like this:
    48-(-40)=88 , and not 48-40=8

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  13. It is wrong as (-8) multiplied by 5 = (-40).Then 48-(-40) as negative and negative equals to 48+40.So the answer is 88.

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  14. It should be
    (-16)x(-3)-(-8)x5
    =48+8x5
    =48+40
    =88

    ReplyDelete
  15. it is:

    (-16)x(-3)-(-8)x5
    =48-(-40)
    =88

    instead of:

    (-16)x(-3)-(-8)x5
    =8
    =48-40

    ReplyDelete
  16. The answer is wrong as (-8)x5 is -40 so if you subtract 48-(-40)equals 88.

    ReplyDelete
  17. The correct answer is:
    (-16)x(-3)-(-8)x5
    =48--40
    =48+40
    =88

    ReplyDelete
  18. Class S1-02

    Well done... all of you are able to identify what's wrong with the working.

    Notice that a few of you put down, as part of your working like
    48--40 or 48 - -40

    Please remember, when we have 2 signs side by side, they have to be separated by the bracket ().

    Cheers!
    Ms Loh

    ReplyDelete