Q&A - P3 Math

[ksme]

Thanks Tianzhu. What about the 2nd qn on apples?


As I said earlier, you are an angel for us parents. 

[tianzhu]

ksme:

Thanks Tianzhu.

Hi

You're welcome.

Best wishes

[tianzhu]

Hi


Hope this helps.

Best wishes.

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[24hr-mum]

tianzhu:

Hi


Hope this helps.

This is a question on “Excess and shortage”.
Some may call it “Gap and Differences” concept.

Best wishes

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thanks a lot, tianzhu and ksme.

re the aziz question, why take the shortage and excess add together and divide by the difference in the number of pens? would be difficult to explain to my girl why do so. even i myself not so sure why.

does the sch actually give this kind of question in exam?
does the sch teach the kids how to do in class?
if yes, so stressful

i got this from andrew er bk. i m always not so sure whr to use assessmt bks cos not sure whc bk's standard is same as the top schools. can anyone advise whc bk?

[tianzhu]

24hr-mum:

re the aziz question, why take the shortage and excess add together and divide by the difference in the number of pens? would be difficult to explain to my girl why do so. even i myself not so sure why.

Hi 24hr-mum

You need to apply a bit of logical reasoning here.

Let take a real life example of going to the hawker centre to buy the famous Teochew paos.

Assuming 1 pao costs $1 and you have $10.

If you buy 7 paos, you’ll have to pay $7, leaving you with an extra of $3.

If you want to buy 12 paos,you need to have $12.This means you are short of $2.

The difference between the number of paos( 12 and 7 ) is 5.

The gap between extra and shortage is $5.

In the Aziz’s question, the exact amount of money he has is unknown.
That’s why we draw a bar to represent his original amount of money which helps one to see the comparison between the two cases (6 and 8 pens)

Hope this helps.

Best wishes

[tianzhu]

24hr-mum:

does the sch actually give this kind of question in exam?

Hi

I am a parent; I can only share with you my experience in helping my kid in Maths during the last quarter of P5 and the PSLE year.

We relied mainly on worksheets given by the school and past years test papers from top schools (free from some websites).

Yes, such questions on “Excess and shortage’ are common in the exams.

Best wishes

[24hr-mum]

tianzhu:

24hr-mum:

re the aziz question, why take the shortage and excess add together and divide by the difference in the number of pens? would be difficult to explain to my girl why do so. even i myself not so sure why.

Hi 24hr-mum

You need to apply a bit of logical reasoning here.

Let take a real life example of going to the hawker centre to buy the famous Teochew paos.

Assuming 1 pao costs $1 and you have $10.

If you buy 7 paos, you’ll have to pay $7, leaving you with an extra of $3.

If you want to buy 12 paos,you need to have $12.This means you are short of $2.

The difference between the number of paos( 12 and 7 ) is 5.

The gap between extra and shortage is $5.

In the Aziz’s question, the exact amount of money he has is unknown.
That’s why we draw a bar to represent his original amount of money which helps one to see the comparison between the two cases (6 and 8 pens)

Hope this helps.

Best wishes

how to present the answer? is it draw models?
does the sch teach or we must somehow source the answers?

[tianzhu]

24hr-mum:

how to present the answer? is it draw models?
does the sch teach or we must somehow source the answers?

Hi

I’d say a MD helps students to arrive at the answers; it helps one to \"see\" Maths.

If you get more familiar with “Excess and shortage “types of questions, you may do away with drawing models.

I believe all questions in school exams should be covered in syllabus.

Best wishes

[rrjan]

Could anyone help me on this question please? How to show answer with model for this qsn?


Linda & Roy have a total of 255 stamps. Half or Linda’s stamps is twice as many as Roy’s stamps. How many stamps does Roy have?

Sincere Thanks,
Jan

[ksme]

rrjan:

Could anyone help me on this question please? How to show answer with model for this qsn?


Linda & Roy have a total of 255 stamps. Half or Linda's stamps is twice as many as Roy's stamps. How many stamps does Roy have?

Sincere Thanks,
Jan

I can't draw model. However, this is how I would work out the answer:

Half of Linda's stamps is twice as many as Roy's stamps
=> all of Linda's stamps would be 4 times as many as Roy's stamps

Total 5 parts (Linda's 4 parts + Roy's 1 part) => 255 stamps.
1 part = 51 stamps.

Therefore, Roy has 51 stamps.