Q&A - P5 Math

[Jcong]

Why do you use multiple of 9? and why is 27 chosen instead of other numbers like 18? So sorry don’t really understand. Thanks

[tianzhu]

Jcong:

Why do you use multiple of 9? and why is 27 chosen instead of other numbers like 18? So sorry don't really understand. Thanks

Hi

C contained 1/9 of the total amount of water the three pails had.
Hence, we use multiples of 9, just to make the calculations easier.

The number of units for Pail A and Pail B add up to 24(7+17).

Hence the total number of units(A+B+C) has to be greater than 24.

Alternatively, you may use MD.

7units (Pail A) +17units (Pail B) + 1part (Pail C) ------- 9 parts (representing A+B+C)

24units ------- 8parts

3units ------- 1part.

Best wishes

[Jcong]

Thank you so much. Now I understand.

[tianzhu]

Jcong:

Thank you so much. Now I understand.

Hi

Good Morning.

You’re welcome.

Best wishes

[pixiedust]

Hi all, please help me the following:


Source : 2010 RGPS P5 SA2
http://orlesson.com/10Ma/2010-P5-Math-SA2-RGPS.pdf

Paper 1, Question 28.
Paper 1, Question 29.

Paper 2, Question 12. Part (a) My answer is $319.50 which is different from answer key.
Paper 2, Question 17.

Thanks in advance.

[tianzhu]

Hi


Hope this helps.

Best wishes.

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[tianzhu]

Hi


For P2 Q17

Part (a) is a gift, the answer is 140cm.

For part (b)

A:B ------- 80:140 -------4:7
Common multiple ------- 28

So you can get 7 pieces of A and 4 pieces of B.

A means plank in figure A (80) and B means plank in figure B (140)

Consider 1 set of A and B

Number of circular stickers ----- 74 -----28

Number of triangular stickers ------ 49 ------36

Total number of stickers ------64

There are (36-28) or 8 more triangular stickers than circular stickers in one set.

136/8 ----- 17

17*64 ------1088.

If you need the slides, please let me know.

Best wishes.

[PiggyLalala]

tianzhu:

Hi


Hope this helps.

Best wishes.

http://farm7.static.flickr.com/6205/6122997729_9ce9c915f3_z.jpg\">

:thankyou: for the solution.
Q28 is really a tough one. I was about to use similar triangles ( which is not in the primary school syllabus) to find the area.

Questions on area can be quite tough. Any techniques/advice/steps for the pupils to think through when solving challenging area questions? Thanks

[tianzhu]

Hi pixiedust


P2 Q12(a) ----- Your answer is correct.

Best wishes

[tianzhu]

PiggyLalala:

:thankyou: for the solution.
Q28 is really a tough one. I was about to use similar triangles ( which is not in the primary school syllabus) to find the area.

Questions on area can be quite tough. Any techniques/advice/steps for the pupils to think through when solving challenging area questions? Thanks

Hi

First, you must have faith in the KS philosophy.

Keep in Syllabus.
Keep it Simple
Keep it Short.

Rearrange the areas into familiar looking shapes; look nothing more than what your teacher taught you in school.

Best wishes