Q&A - PSLE Math

[PiggyLalala]

tianzhu:

PiggyLalala:

Thank you for showing us another way doing this question.

I love your way of transforming a difficult question to one that students are familiar with. I feel that this way of teaching is especially good for the weaker students.

Good luck to all your students in their coming PSLE too. :rahrah:

Hi

You're welcome.

I think some students may be caught off guard by this question.
It is actually a familiar question with a slight tweak.

The assumption, “Assume all were books” in this particular question is written as a statement in the question.

Students who understand the concepts should be able to see that the additional number of books is equal to the number of pens. The $20 is due to the book costing $2.50 more than the pen.

My students?

I've no students.

I am not a teacher, I am a simple dad of a post PSLE kid.

Best wishes

Oh sorry.. I thought I have read from previous posts that you are a tutor. Sorry i could have make a mistake.

[tianzhu]

PiggyLalala:

Oh sorry.. I thought I have read from previous posts that you are a tutor. Sorry i could have make a mistake.

Hi PiggyLalala

No worries, enjoy your holidays.

Best wishes

[SaPan]

need help on below question.


some workers arranged chairs in 18 short rows and 7 long rows.
each long row had 32 more chairs than short rows.
half of the chairs were arranged in long rows while 3/7 of the chairs in short rows.
remaining chairs are stacked in a corner.

How many chairs were arranged in rows?

many thanks in advance.

[tianzhu]

SaPan:

some workers arranged chairs in 18 short rows and 7 long rows.
each long row had 32 more chairs than short rows.
half of the chairs were arranged in long rows while 3/7 of the chairs in short rows.
remaining chairs are stacked in a corner.

How many chairs were arranged in rows?

Hi

Long rows (LR) ------ 7 units (1/2 of 14)
Short rows (SR) ------ 6 units (3/7 0f 14)
Stacked up chairs ------ 1 unit

6 units ------ 18SR
1 unit ------ 3SR

1LR ------ 1SR + 32
7LR ------ 7SR + (7*32) ------7SR + 224

You may use MD to compare
7SR + 224 ------- 18SR + 3SR
14SR ----- 224
1SR ----- 16
\t
1 unit ---- 3SR ----- 48
13 units ----- 13*48 -------- 624

Number of chairs (rows) ------ 624

Best wishes

[dnsy]

Hi. Stuck with a question from hokkien huay kuan 2009 Maths preliminary…


A car and a coach travelled from Town A to town B. The coach left town A at 0648 and it took 5 hours to reach town B. The car started 30 minutes later than the coach and it took 4 hours to reach town B. At what time did the car catch up with the coach?

The answer sheet shows 0918 but there is no working…

Thanks!

[tianzhu]

dnsy:

A car and a coach travelled from Town A to town B. The coach left town A at 0648 and it took 5 hours to reach town B. The car started 30 minutes later than the coach and it took 4 hours to reach town B. At what time did the car catch up with the coach?

Hi

This question was discussed in an earlier post.

Please follow this link.
http://www.kiasuparents.com/kiasu/forum/viewtopic.php?f=69&t=280&hilit=0648+5h&start=1500

Best wishes

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[cimman]

pixiedust:

I interpreted the problem as 'total value / amount before transfer and after transfer should be the same'. Will update all when the teacher explains the solution.

yes, do let us know. It is hard enough to get a child to solve difficult maths problems without having to contend with the interpretation of the problem statement. With a few more words, they could have made the problem statement more defined and not leave room for interpretations.

[TT2]

Hi. Can anyone help with this qn?


Elisa, Fiona and Gina had a collection of stamps. Fiona n Gina collected 7/10 of the stamps. Elsa n gina collected 5/7 of the stamps. Elsa n Fiona collected 697 stamps altogether. How many more stamps did Gina collect than Elsa?

TIA

[comfy]

PiggyLalala:

comfy:

I understand the step till extra books bought 20/2.5=8

But can explain the next step? why need to 50-8?

Let me try again.
8 extra books here mean if Mary buys 50 books, then it will be 8 more than the number of books she bought at first.

Hence the number of books that mary bought at first = 50 - 8 = 42.

Sorry i am not very good in explaining how i arrive at my answer. Hope you can understand. Maybe others can help. You can also look at Tianzhu's solution.

Thanks Tianzhu & PiggyLalala for solving the problem. Just need to get used to the way how it solved by both of u. Thinking whether it can be solved by model method as my dd is more familiar to that.

[carebear]

TT2:

Hi. Can anyone help with this qn?


Elisa, Fiona and Gina had a collection of stamps. Fiona n Gina collected 7/10 of the stamps. Elsa n gina collected 5/7 of the stamps. Elsa n Fiona collected 697 stamps altogether. How many more stamps did Gina collect than Elsa?

TIA

Common denominator is 70.
Total no of units = 70

E + F + G = 70 units

F + G = 49 units cos 7/10 = 49/70
E + G = 50 units cos 5/7 = 50/70

E = 70 - 49 = 21 units
F = 70 -50 = 20 units

E + F = 697 stamps
21 units + 20 units = 697 stamps
41 units = 697 stamps
1 unit = 17 stamps

E + F + G = 70 units
G = 70 units - (E+F) = 70 (17) - 493 = 493 stamps.

E = 21 units = 21 (17) = 357 stamps.

G - E = 136 stamps.