## Monday, 20 January 2014

### Review: Homework Chap 1 Q4

Workbook (p2) Q4: Find the prime factorisation of each of the following numbers, leaving your answer in index notation

Examine the following working:
(1) Has the student answered to the question? If not, what's wrong in the way the answer is presented?
(2) Is the overall working clearly presented to demonstrate the student knows what he/she needs to find? If not, how could the working/ presentation be improved?

* Afternote was added to the end of each case, after discussion with the class on 20 January.

Case 1:

Afternote:
The student had done the Prime Factorisation correctly.
The question asked for prime factorisation and answers be presented in Index Notation.
However, the student did not answer to the question. Instead, he/ she listed all the factors of the number, which is not required.

Case 2:

Afternote:
The student had done the Prime Factorisation correctly.
However, he/ she did not understand what is meant by 'index notation' (see the arrow he/ she drew, pointing at "1").
In addition, though he/ she had written "2^3 x 7 x 11 x 13", his/ her final answer was 8008.

Case 3:

Afternote:
The student had done the Prime Factorisation correctly.
3^2 (5 x 7) is a mixed presentation of "multiplication". He/ She should have written it as 3^2 x 5 x 7.
In addition, from the presentation, he/ she had 315 as the final answer. So, it is an indication of not understanding what "index notation" means.

Case 4:

Afternote:
The student had done the Prime Factorisation correctly.
(2^3 x 7) x (11 x 13) is a mixed presentation of "multiplication" and the "operation"/ working seemed incomplete. He/ She should have written it as 2^3 x 7 x 11 x 13

Case 5:

Afternote:
The student had done the Prime Factorisation correctly; however, he/ she had not carried it out in a systematic manner.
As a good practice, we should always test the division with the smallest possible prime number (divisor) before moving on to the next one so that we need not to do further "random checks" in subsequent divisions - for the ease of checking and accounting for all possible prime factors involved.

Similarly, when writing the product of prime factors in index notation, It would also be a good practice to start with the smallest prime factor (in ascending order) - for the ease of checking.

Discuss it as a group and comment for all the cases

Remember to sign off with your Group number.

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4. Group 1
Case 2
The student has answered the question and there is nothing wrong with the presentation

5. Group 1, Elgin Ng
Case 4:
1. He/she does not have to put brackets.
2. The overall working clearly presented to demonstrate the student knows what he/she needs to find

6. gp4 case 5 8008/11=728 not1144

7. Group 3: Khoo BOsi
case3
doesnt need a bracket

8. the student did not list the factors not the multiples gp4 case 1

9. Group 1: owen
Case 3
1. the person does not need to put the brackets for 5]the numbers 5 and 7.
2.When done, the person should put ANS or double stroke his or her answer.

10. Group 2: Javier Liew
Case 4
U dont have to bracket the answer

11. GRP2, Wong Kang
CASE3: The 3^2(5X7) Should be written as 3^2X5X7 and that would be the ans instead of 315

12. Grp 1 Joshua Chua
Case 5
The first three prime numbers should be 2 followed by 7,11,13
but the answer is still correct

13. Group 3: Low Tjun Lym
Case 2
The arrow pointing to the '1' is not correct as index notation is not represented there. The arrow should point to the answer as it is left in index notation.

14. Group 2, Celest Oon
Case 2:
1. The number 1 is not the index notation.
2. He did not label his answer.

15. group 2
joshua yew
case 1 the answer has to be written like this : 2^3X7X11X13

16. Group 4,Dominic Hong
Case 3: Forgot to write the multiplication sign at the bracket and the bracket isn't necessary.
Never put like 3x3x5x7

17. Group 4: Woon Yoke Xuan
Case 4:
There isn't a need for the bracket to "group" the numbers.

18. Group 3: Christopher Yong
Case 5
It is not systematic and you should always start with the smallest number possible.

19. Group 2: Fyodor Lee
Case 2
The working and the presentation was both fine.

20. Group 6
Moon Gijoo
Case 5

Yes.
No. During the prime factorisation, lowest prime number should the one to be divided first.

21. Group 5 Joel Tio
Case 3
Missing line below 1.
Missing Ans.
Missing multiplication sign.

22. Group 5 Joel Tio
Case 5
Non-systemactic
Missing Ans.

23. group 5
case 2
javier yeo
The student did not draw a line between the 8008 and 4004 of the chart.
The 8008 is supposed to go before the number sentence.
The index notation is not the number 1

24. Group 5
Case 4
The numbers don't have to be bracketed as there is only multiplication in the whole equation