Friday, February 3, 2017

Error Analysis

3 Feb: Evaluate the following solution done by 2 students. 

Group Work (identify a scribe to key in your group's responses).
As usual write the name and index number of your group's members.

Your Task
  • Analyse the solution provident by student A and student B for accuracy or process (method) and clarity or working.
  • State the nature of error, eg. 'wrong use of operation rule', '(-) x(-) should not be (-)' etc
  • Give your solution to both students.
  • post your evaluation and solution as 'comment' [remember to include name and index number]

Marking criteria
  • Mathematical Appropriateness of your evaluation: 5 marks
  • Your solution: 5 marks

Student A' s solution

student B's solution


15 comments:

  1. Adabel Teoh Yujia (1)
    Student A:
    Student A adding the 2 mix numbers together but he was actually suppose to go in order, so he should first (-) then (-) again and lastly (+) and he should have gotten -2 2/3
    Student B:
    Student B multiplied instead of dividing the last equation. If he had divided the answer should have been 10

    ReplyDelete
  2. Yeo Teng Jun (24)
    Student A:
    Student A should change 5/4 and 3/2 converted into mixed number. He should start from left to right so the answer should be -2 2/3.
    Student B:
    Student B mistakenly multiplied instead of dividing in the last equation. His answer should have been 10.

    ReplyDelete
  3. Chua Xing Zi (03)
    Student A:
    The final answer for student A's solution should be -2 2/3 instead of 7 1/3. This is because student A should follow the right order and minus before he plus. So, in the end his answer was wrong.

    Student B:
    The final answer for student B's solution should be 10. If student B has not multiplied in his last equation he would have gotten the right answer but he when to multiply instead of dividing the last equation. Thus, he arrived at the wrong answer.

    ReplyDelete
  4. Damien Tan (21)
    Student A:
    Line 4 is wrong as he should not have done 5 3/12 + 2 4/12. He should do the working step by step and add and subtract from left to right. Hence, due to to his wrong use of operation rule, his answer and working are wrong.
    Correct solution:
    √9/4 - ∛125/64 - 5 1/4 + 2 1/3
    = 3/4 - 5/4 - 5 1/4 + 2 1/3
    = 18/12 - 15/12 - 5 3/12 + 2 4/12
    = 3/12 - 5 3/12 + 2 4/12
    = -5 + 2 4/12
    = -2 8/12
    = -2 2/3

    Student B:
    Instead of finding the quotient in the last equation, Student B found the product. Therefore, due to his wrong use of the operation rule, his answer is incorrect.
    Correct solution:
    (-1/2 - 1/3) / [-1/4 -(-1/6)]
    = (-3/6 - 2/6) / [-1/4 + 1/6]
    = -5/6 / [-3/12 + 2/12]
    = -5/6 / (-1/12)
    = 10

    ReplyDelete
  5. Student A: He did not use the correct order to solve the equation when 3/12 should -5 3/12 and not add both 5 3/12 with 2 4/12 together.
    Correct solution: 3/12-5 3/12+2 4/12=-5+2 4/12=2 8/12 =2 2/3

    Student B: This student instead of multiplying he went on to divide and he got 5/72 when it should be 10
    Correct solution: (-1/2-1/3)/[-1/4-(-1/6)]= -5/6[-3/12+2/12]= -5/6 / (-1/12)=10

    ReplyDelete
  6. Student A:What Student A did wrong is that he used 5 3/12 + 2 4/12,that means he added the values together as a whole instead of adding them individually step by step.
    The correct method should be 3 / 12-5 3/12 + 2 4/12=5+2 4/12=2 8/12=2 2/3

    Student B:What he did wrong was that for the last step,he found the product of the equations instead of the number after it was divided,that was why he got 5/72 instead of 10.
    The correct method should be (-1/2 - 1/3) / [-1/4=(1/6)] which equals to -5/6(-3/12+2/12]= -5/6 / (-1/12) which gets you the answer of 10.

    ReplyDelete
  7. This comment has been removed by the author.

    ReplyDelete
  8. Ariel (2)
    Student A: Student A did not follow the order of operation. He subtracted 3/2 and 5/4, and added 5 1/4 with 2 1/3. He was supposed to go from left to right.
    3/2 - 5/4 - 5 1/4 + 2 1/3 = 2 2/3.

    Student B: Student B multiplied instead of dividing the equation.
    (-3/6 - 2/6) / (-1/4 + 1/6)
    = -5/6 / -1/12
    = 10

    ReplyDelete
  9. Student A did 5 3/12 + 2 4/12 so he added them altogether instead of slowly adding them individually.He should have done 3/2-5/4-5 1/4+2 1/3 which would be 2 2/3
    Student B multiplied instead of divided
    (-3/6-2/6) x (-1/4+1/6)
    =10

    ReplyDelete
  10. This comment has been removed by the author.

    ReplyDelete
  11. timothy luk (23)
    student A did not follow the order of operation. the correct answer should be -2 2/3
    student B needs to divide, not multiply

    ReplyDelete
  12. Joel (22)
    Student A: He did not follow the correct operation. He should add then subtract
    Student B: He should divide not multiply first
    Answer: 10

    ReplyDelete
  13. Kwa Wei Le(12)
    Student A:
    Student A did not follow the correct order of operation. He added the two mix numbers together but he was actually suppose to go in order, so he should first minus then minus again and plus and he should have gotten -2 2/3.
    Student B:
    Student B divided instead of multiplying for the last equation. If he did it correctly, the final answer should be 10.

    ReplyDelete
  14. Audrey Peh (5)

    Student A did not follow the order of operation. He should go from left to right.
    3/2 - 5/4 - 5 1/4 + 2 1/3 = 18/12 - 15/12 - 5 1/4 + 2 4/12 + -2 2/3

    Student B had multiplied instead of divide.
    5/6 / (-1/12) = 10

    ReplyDelete
  15. Hansen Wee (10)

    This A Student did not follow the order of operation, instead of his way, he should go from left to right

    This B Student did this -5/6x9-(1/12), he should have changed the divided instead.

    ReplyDelete

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