## 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.

1. Case 1: He is stating the factors not the index notation and he should only take the prime factors which are on the left side of the table.

Case 2: '1' is not the index notation.

Case 3: '315' is not an index notation.

Case 4: The answer is not an index notation.

Case 5: The table should have the numbers in ascending order.

Done by:Group 4

1. 1 point for each part.
Total: 5 points for group 4

2. (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?

Case 1. He has not answered the question. He put in the factors, not the index notation. The overall working is not clearly presented. He could write the number statements down.

Case 2. He has not answered the question. He put in the answer to the index notation, not the index notation itself. The overall working is not clearly presented.
By Group 3

1. 1 point for each part.

2. Total: 2 points for Group 3

3. (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?

Case 1: The student didn't draw the lines for the presentation and the student gave the factors but the question was not asking for factors.
Case 2: The answer is not the index notation and that was what the question was asking for besides the student did not draw the lines.
By: Sophia, Joshua, Jin Yu, Everi, Shanice, Ming Quan.

1. 1 point for each part
Total: 2 points

4. Case 1: The answers are not in index notation

Group 2

5. case 2: The Index notation is wrongly indicated
Case 3: The brackets are not needed and the answer is not in index notation
Case 4: The brackets are not needed and the answer is not in index notation
Case 5: The numbers should be in ascending order.

Group 2

6. For case 2, was not even in index notation.
For case 5, you should be more specific - instead of calling it 'number', should use the term, 'prime factor'
Total: 3 points