Q&A - P3 Math

[jedamum]

ChiefKiasu:

jedamum:

I'll probably use trial and error method and hope that she is not giving out >100 balloons. :lol:
Ans: 2 students...correct?

That's what we will get when we use algebra, ie. solve for:
6x + 2 = 8x - 2
=> 2x = 4
=> x = 2

Just that the case in question is given the answer of 14 in \"illegal\" black-market exam papers. Shows how bad the answers can be! So don't trust the answers provided.

Also, it is difficult with people not trained to do modelling to work out this problem without algebra.

illegal black-market exams papers aside, nowadays assessment books in the market also have typo, questions and answers error!

[lizawa]

For P3, I expect this question to test on multiplication / division + process skills.


Multiples of 6 : 6, 12, 18,24, …
+2 (since 2 balloons left) : 8, 14, 20, 26…

Multiples of 8 : 8, 16, 24, 32, …
-2 (short of 2 ballons) : 6, 14, 22, 30…

Since asking for smallest number of students, the number that match in both cases is 14, hence, number of students is 2.

Liz

[ChiefKiasu]

lizawa:

For P3, I expect this question to test on multiplication / division + process skills.


Multiples of 6 : 6, 12, 18,24, ...
+2 (since 2 balloons left) : 8, 14, 20, 26...

Multiples of 8 : 8, 16, 24, 32, ...
-2 (short of 2 ballons) : 6, 14, 22, 30....

Since asking for smallest number of students, the number that match in both cases is 14, hence, number of students is 2.

Liz

OK... Liz is the one with the right answer and methodology. All of us are \"old school\". Back to school, everyone.

[lizawa]

Yeah, when you have to coach your own children from P1 - P6 with all the new-aged methods and syllabus, the only way is to unlearn and relearn.


Liz

[phantom]

Talking about unlearn, where can I get information on those new methods?

[lizawa]

I follow through my children’s text books and look at some of the guide books. Take a while to get used to. The modelling method that they use for Primary Mathematics is very visual. So your child needs to be able to visualize in order to draw the model and solve the problem. It’s just another way of solving problems.


Liz

[phantom]

lizawa:

I follow through my children's text books and look at some of the guide books. Take a while to get used to. The modelling method that they use for Primary Mathematics is very visual. So your child needs to be able to visualize in order to draw the model and solve the problem. It's just another way of solving problems.


Liz

Wow, looks like a lot of right brain training here. I will start looking at my niece textbook to prepare myself. Thanks for the info!

[lizawa]

Hello phantom,


no need to start preparation so early. saw in another thread that your kid will only be in P1 3 years' time. MOE is revising the Maths syllabus already. Starting from next year P5, calculators are allowed for PSLE maths. Which means that instead of 1 paper now, the students have to sit for 2 papers for MAths, 1 with calculator and the other without calculator. :shock:

So not sure if it's good news or bad news.

[phantom]

lizawa:

Hello phantom,


no need to start preparation so early. saw in another thread that your kid will only be in P1 3 years' time. MOE is revising the Maths syllabus already. Starting from next year P5, calculators are allowed for PSLE maths. Which means that instead of 1 paper now, the students have to sit for 2 papers for MAths, 1 with calculator and the other without calculator. :shock:

So not sure if it's good news or bad news.

Thanks for the cue. Seems like MoE has been changing syllabus very frequently these years, hard to catch up.

I suppose allowing calculator just means the paper will be more difficult. I remember the time when I have open book exam and what it just mean is you can hardly find the answer in the book.

[ChiefKiasu]

Here’s another one, this time from Catholic High Primary 3 SA1:


Gregory and Timothy has 192 stickers together. After Timothy gave 30 stickers to Gregory, Timothy had thrice as many sticker as Gregory. How many stickers did Gregory have at first?

Again… no algebra please.