Q&A - PSLE Math

[thinkgmama]

Hi,


I would like to ask

36+2 ------ 38 ($2 is already added)
6+4 ------80 ( $4 is already added)

How come at the end,

Shoes ----- 38+2 ------ 40 (why do we need to add $2 again?)
Handbag --------80+4 ------84 (why do we need to add $4 again?)

Please kindly help to explain. Thank you very much.

tianzhu:

homeworkmummy:

I need help for another 1 Qs from Nan Hua paper.

Mrs Samy had a sum of money to spend. She spent 1/2 of her money plus $4 on a handbag. She then spent 1/2 of the remaining money plus $2 on a pair of shoes. Finally she spent 2/3 of what was left plus $1 on a skirt. She was then left with $11.
(a) How much did each item cost?
(b) How much money did she have at first?

Hi

You may use “Working backwards” and show it using MD.

1/3 ------- 11+1 ------ 12
3/3 -------12*3 ------ 36

36+2 ------ 38
38*2 ------ 76

76+4 ------80
80*2 ------ 160

Skirt ----- 24+1 ------ 25
Shoes ----- 38+2 ------ 40
Handbag --------80+4 ------84

Amount of money at first ------160

Best wishes

[MathIzzzFun]

thinkgmama:

Hi,


I would like to ask

36+2 ------ 38 ($2 is already added)
6+4 ------80 ( $4 is already added)

How come at the end,

Shoes ----- 38+2 ------ 40 (why do we need to add $2 again?)
Handbag --------80+4 ------84 (why do we need to add $4 again?)

Please kindly help to explain. Thank you very much.

tianzhu:

[quote=\"homeworkmummy\"]I need help for another 1 Qs from Nan Hua paper.

Mrs Samy had a sum of money to spend. She spent 1/2 of her money plus $4 on a handbag. She then spent 1/2 of the remaining money plus $2 on a pair of shoes. Finally she spent 2/3 of what was left plus $1 on a skirt. She was then left with $11.
(a) How much did each item cost?
(b) How much money did she have at first?

Hi

You may use “Working backwards” and show it using MD.

1/3 ------- 11+1 ------ 12
3/3 -------12*3 ------ 36

36+2 ------ 38
38*2 ------ 76

76+4 ------80
80*2 ------ 160

Skirt ----- 24+1 ------ 25
Shoes ----- 38+2 ------ 40
Handbag --------80+4 ------84

Amount of money at first ------160

Best wishes

[/quote]Hi

hope this model will help ...

http://i41.tinypic.com/zwto7.jpg\">

cheers.

[YumYum]

Hi, pls help with the following :

Sandy and Nicole had $60 at first.Sandy and Nicole spent some money. The amount of money Sandy spent was twice the amount of money Nicole spent. Nicole had $10 more then Sandy in the end. What Nicole had was also twice of what Sandy had in the end.
a) Find out how much did Nicole spend.
b) Find out how much Sandy had at first.
Thnks!

[MathIzzzFun]

YumYum:

Hi, pls help with the following :

Sandy and Nicole had $60 at first.Sandy and Nicole spent some money. The amount of money Sandy spent was twice the amount of money Nicole spent. Nicole had $10 more then Sandy in the end. What Nicole had was also twice of what Sandy had in the end.
a) Find out how much did Nicole spend.
b) Find out how much Sandy had at first.
Thnks!

Hi

In the end, Nicole had twice as much as Sandy and Nicole had $10 more than Sandy.

So, Nicole --> $20, Sandy --> $10, total spent --> $30
Total amount spent --> $60 - $30 = $30
Sandy spent twice as much as Nicole, Nicole's spending --> 1/3 x $30 = $10
At first, Sandy --> $10 + $20= $30

cheers.

[ET-PH]

Thanks MathIzzzFun and Speedmaths.com

[speedmaths.012624com]

kamom:

Help :please:


http://img.photobucket.com/albums/v606/shirleywoon/SH-Sep2011/MathOlympiadTest1e.jpg\">

THANKS A MILLION

http://i44.tinypic.com/w8173p.jpg\">

Hi kamom,

The answer is 55 degrees.

Please see diagram.

First, draw a square, say 1 cm by 1 cm.
Next, draw an isosceles triangle on the right, and use trigonometry to find the value of lengths a, b and c.
Then draw another isosceles triangle on the left, and use trigonometry to find the value of lengths d, e and f.

g = c - e

w + x = 70 degrees

tan (w + 70 degrees) = (f + 1 + b) / g

x = (70 degrees - w) = 55 degrees.

The solution I used involves trigonometry, which is normally beyond P6 pupils.

May I know the source of this question?

Cheers


Speedmaths.com
http://www.kiasuparents.com/kiasu/forum/viewtopic.php?f=43&t=25433&start=10


.

[thinkgmama]

Thank you do much. I finally understand.

[homeworkmummy]

tianzhu:

homeworkmummy:

Could you pls advise if this can be solved by model method. My DD was confused with the percentage method.

Hi

It’s possible to provide graphical representations of the information in the question.

Perhaps you may want to check with your DD.

What is confusing her?

What is her understanding of percentages after reading her textbooks?

What is her understanding on comparing two quantities of percentages?

Percentages is first started in P5 Maths.Maybe, she is confused because her teacher has not covered the topic in Percentages for her P6 syllabus yet.

Best wishes

Thanks tianzhu. She is not familiar with the comparison method. Is this only cover in p6?

[tianzhu]

homeworkmummy:

Thanks tianzhu. She is not familiar with the comparison method. Is this only cover in p6?

Hi

Good Morning.

You're welcome.

“Finding percentage increase/decrease” is only covered in P6 syllabus.

http://www.moe.gov.sg/education/syllabuses/sciences/files/maths-primary-2007.pdf

Best wishes

[homeworkmummy]

tianzhu:

homeworkmummy:

Thanks tianzhu. She is not familiar with the comparison method. Is this only cover in p6?

Hi

Good Morning.

You're welcome.

“Finding percentage increase/decrease” is only covered in P6 syllabus.

http://www.moe.gov.sg/education/syllabuses/sciences/files/maths-primary-2007.pdf

Best wishes

Thanks Tianzhu for the info.