Math Error Analysis (Chelsea)

Math Error Analysis Kai Cheng 19

Diagnostic Test 2 Q4 (c)

QD
Line 1 (Carelessness): 2(11/9) =2x2.
Line 2 (Conceptual) :(-) x (-) = (+), not (-), and it is multiplication, not addition.

QE
Line 1 Conceptual): 2 (11-9) = 2(2), not 22-18.You have to do the bracketed formulas first.

QF
Line 2 (Conceptual):2 (11-9) =2(2), not 22-18, because the bracketed formulas must be done first, same goes for the 16 (-1/2)^2, you have to get (-1/2)^2 first.

Diagnostic Test 2 Q4 (cd)

QA
Line 1( Carelessness): 2/3 x 1/4 should be = to 1/6.
Line 2 (Carelessness): -1/2 / 1/6= -3

QB
Line 2 (Conceptual): -1/2 / 1/6 = 3

QC
Line 1( Conceptual):1/2 - 1 = (-1)
                                2/3 x 1/4 = 1/6

QD
Line 4(Conceptual) :-1/2 / 1/6 = 1/2 x 6/1, you must flip the second number.

QE
Line 2 (Carelessness) :-0.5 / 0.5/3= -3

Error analysais (Eunice)

Diagnostic test 2Q4 (c)
D)
Nature of errors: careless
Line 1
11-9=2,
Then it is
=2(2)
=4.

Nature of errors: conceptual
Line 2
The student adds the two fractions together instead of multiplying it, where nessasry.
So,
-½ x -½
=-¼

E)
Nature of errors: conceptual
Line 1
When solving an equation, solve the problem in the bracket first.
So, if 11-9=2,
Then it is
2(2)
=4

F)
Nature of error: conceptual
Line 1
2(11-9) is not (22-28), the problem in the bracket must be solved first.
Thus,
11-9=2,
2(2)=4
Line 1
conceptual
Only ½ in the equation should be squared and 16 should not.

Diagnostic test 2 Q4(d)
A)
Line 2
Nature of error: conceptual
2/12 is not 6.
The student have used 12 divided by two instead of using two divided by 12.


B)
Line 2
Nature of error:careless
When
⅔ x ¼ ,it is
2/12
instead of
1/12 =⅙
C)
Nature of error:careless
Line 1
The student have added ½ and -1 instead of subtracting 1 rom ½.
Is should be ½-1= -1 ½
The student multiplied ⅔ and ¼ wrongly. It should be ⅙ instead of 11/12

nature of error: conceptual
Line 1
⅔ x ¼ is not ⅓ x ½ , but the student wrote ⅓ x ½ as ⅔ x ¼.

E)
nature of error: conceptual
Line 1
The change of form from fraction form to decimal form is redundant.

Error Analysis (Xue Qin)

Error Analysis -(Bryan Goh)

Diagnostic Test 2:

Question 4(c):

QD:
Line 1: (Careless)

2(11-9) = (2x2)
       not: (2x3)

Line 2: ) (Conceptual)

(-1/2 x -1/2) = +1/4
              not: -1

QE:
Line 1: (Conceptual)

(1/2)^2 = +1/4
       not: (-0.25)
Note: (-) x (-) = (+)

QF:
Line 2: (Conceptual)

16(-1/2)^2 = 16(1/4)
                  =4
            not:(16 x -1/2)^2 = 8


Question 4 (d):

QA:
Line 2: (Conceptual)

Should be: -1/2
                 --------
                   1/6

QB:
Line 3: (Conceptual)

-1/2
------ = -1/2 x 6
 1/6
        = 3

QC:
Line 1: (Careless)

1/2 - 1 is not 1/2 + 1
 (-1/2)            (1.5)

2/3 x 1/4 = 1/6

QD:
Line 4: (Conceptual)

(-1/2)
------- = (-1/2) x 6/1
  1/6
    not: (-2/1) x 1/6

QE:
Line 1: (Conceptual)

2/3 x 1/4 is not 2/3
                       ------
                        4/1

Error analysis Luke

Diagnostic Test 2 Q 4 (c)
QD
Nature of errors:Careless
Error:
Line 1:
2 x 2 - 16 x -1/2 x -1/2=0
Line 2:
2 x 2 - 16 x 4= -60 

Diagnostic Test 2 Q 4 (c)
QE
Nature of errors:Conceptual 
Error:
Line 1:
22 - 18 - 16 (0.25)=-3

Diagnostic Test 2 Q 4 (c)
QF
Nature of errors:Conceptual 
Error:
Line 1:
22 - 18 - 16 x -1/2 x -1/2 =4

Diagnostic Test 2 Q 4 (d)
QA
Nature of errors:Careless
Error:
Line 2:
-1/2 / 1/6 = -3

Diagnostic Test 2 Q 4 (d)
QB
Nature of errors:Carless
Error:
Line 3:
-1/2 x 6/1 = -3

Diagnostic Test 2 Q 4 (d)
QC
Nature of errors:Careless 
Error:
Line 1:
-1/2 / 1/6 = -3
Line 3:
-18/12 /11/12 = -1 7/11 

Diagnostic Test 2 Q 4 (d)
QD
Nature of errors:Conceptual 
Error:
Line 1:
-1/2 / 1/3 x 1/2
Line 4:
-1/2 x 6/1 

Diagnostic Test 2 Q 4 (d)
QE
Nature of errors:Careless 
Error:
Line 3:
-0.5/0.5/3 = -3 









          
                     

ERROR ANALYSIS - NUMBERS

By Mr Johari
courtesy of Ms Loh KY

Identify the Errors in each of the following solutions as shown by some of the students.
State the nature of errors (conceptual or careless)  and why part of the solution is wrong.

Example 1
Diagnostic Test 2 Q 4 (c)
QA
Nature of errors:  Conceptual
Error:
Line 1   (-1/2)^2 = 1/4
Line 4   (-) x (-) = +

Example 2

Diagnostic Test 2 Q 4 (c)

QB

Nature of errors:  Conceptual

Error: 

Line 2   (-16)(-1/2) = +8

Line 4   (+8) x (-1/2) = -4 incidentally answer right but method wrong therefore 0 mark

Example 3

Diagnostic Test 2 Q 4 (c)

QC

Nature of errors:  Careless

Error: 

Line 2   (-1/2)^2 = 0.25