Q&A - PSLE Math

[ozora]

MathIzzzFun:

ozora:

[quote=\"MathIzzzFun\"]
Hi ozora,

Aaron had 8 units + 8, so 1/8 = 1/8 of 8 units + 1/8 of 8 = 1 unit + 1

cheers

[/quote]oic
thanks

[tianzhu]

Hifive:

Hi Tianzhu

Thanks for the explanation! Your explanation is very clear and I can manage with the models on my own. Thanks for your help!

Hi

You're welcome.

Best wishes

[tianzhu]

Belle2011:

Is the above correct?

Hi Belle

You are on the right track.

You have to convert to value of money for the answer.

Best wishes

[Lynn2]

Hi MathIzzzFun



Thanks, I will show it to dd to see she can understand.

This kind of coins questions has been stuck in her since pri five, no matter how I try to explain to date, still cannot clear.Other topics, all can clear, cos she understand.
In the recent exam, she has to do 18 times of guess and check just to get the answer.I think its quite a waste of time tho she eventually gets the answer.


Cheers


Hi Tianzhu,

Thanks for the explanation.I will try to explain to dd .Can u help another similar question?

5 There were twice as many fifty cent coins as twenty cent coins in a coin box.Stephanie added in some ten cent coins into the coin box and the total amount became $11.30.If there were 9 more ten cent coins than twenty cent coins, how many coins of each type were in the coin box?

Thanks and good day.

Lynn2

tianzhu:

Lynn2:

Box A contains 50 cent coins and Box B contains $1 coins.Box A contains 17 more coins than Box B.The amount of money in Box A is $15.50 less than in Box B.Find the total amount of money in the boxes

Hi

Assume or pretend that the number of coins in Box B is equal to that of Box A

17*1 ------ 17
17 + 15.5 ------- 32.5

Difference between $1 and 50 cents -------50 cents

3250/50 ------65 50 cents coins

Hence, 48 $1 coins

48 + 32.50 -------- 80.50

Best wishes

[/quote]

Hi Lynn2

Hope this will help.


http://postimage.org/image/drdoc9wk/

cheers.[/quote]

[Lynn2]

Hi MathIzzzFun



Thanks, I will show it to dd to see she can understand.

This kind of coins questions has been stuck in her since pri five, no matter how I try to explain to date, still cannot clear.Other topics, all can clear, cos she understand.
In the recent exam, she has to do 18 times of guess and check just to get the answer.I think its quite a waste of time tho she eventually gets the answer.


Cheers


Hi Tianzhu,

Thanks for the explanation.I will try to explain to dd .Can u help another similar question?

5 There were twice as many fifty cent coins as twenty cent coins in a coin box.Stephanie added in some ten cent coins into the coin box and the total amount became $11.30.If there were 9 more ten cent coins than twenty cent coins, how many coins of each type were in the coin box?

Thanks and good day.

Lynn2

tianzhu:

Lynn2:

Box A contains 50 cent coins and Box B contains $1 coins.Box A contains 17 more coins than Box B.The amount of money in Box A is $15.50 less than in Box B.Find the total amount of money in the boxes

Hi

Assume or pretend that the number of coins in Box B is equal to that of Box A

17*1 ------ 17
17 + 15.5 ------- 32.5

Difference between $1 and 50 cents -------50 cents

3250/50 ------65 50 cents coins

Hence, 48 $1 coins

48 + 32.50 -------- 80.50

Best wishes

[/quote]

Hi Lynn2

Hope this will help.


http://postimage.org/image/drdoc9wk/

cheers.[/quote]

[Dharma]

Lynn2:

Hello all,


Can someone pls help this question.Have tried to teach dd to use set method to do this question, but always ended up using guess and check which is very time consuming.She cannot understand the explanation even I tried .

Any kind soul can help?
Here it goes:

1 Box A contains 50 cent coins and Box B contains $1 coins.Box A contains 17 more coins than Box B.The amount of money in Box A is $15.50 less than in Box B.Find the total amount of money in the boxes

Thanks and sure hope dd can clear this type of question.

Cheers
Lynn2

Difference in number of coins => 1u - 1p = 17
Difference in the value of the coins => 100cents (1p) – 50(1u) = 1550
100p - 50u = 1550
2p – 1u = 31
1p = 17 + 31 = 48
1u = 48 + 17 = 65

Total amount of money = (65) x 50 cents + (48 ) x 100 cents = 8050 cents = $80.50

[Lynn2]

Hi Dharma,


Thank you for showing me another way in looking at this question.

Will walk thr the various methods that ksp has worked out and see whether she can see it.She believe in able to understand it rather than route learning.


Thanks.



cheers

Dharma:

Lynn2:

Hello all,

Can someone pls help this question.Have tried to teach dd to use set method to do this question, but always ended up using guess and check which is very time consuming.She cannot understand the explanation even I tried .

Any kind soul can help?
Here it goes:

1 Box A contains 50 cent coins and Box B contains $1 coins.Box A contains 17 more coins than Box B.The amount of money in Box A is $15.50 less than in Box B.Find the total amount of money in the boxes

Thanks and sure hope dd can clear this type of question.

Cheers
Lynn2

Difference in number of coins => 1u - 1p = 17
Difference in the value of the coins => 100cents (1p) – 50(1u) = 1550
100p - 50u = 1550
2p – 1u = 31
1p = 17 + 31 = 48
1u = 48 + 17 = 65

Total amount of money = (65) x 50 cents + (48 ) x 100 cents = 8050 cents = $80.50

[Dharma]

Lynn2:

Hi Dharma,


Thank you for showing me another way in looking at this question.

Will walk thr the various methods that ksp has worked out and see whether she can see it.She believe in able to understand it rather than route learning.


Thanks.

No worries Lynn2.
Your girl definately has the right attitude towards learning. Good luck!

[Lynn2]

Hi Dharma,


Thank you.

She used to do math via rote learning, only realised that it din work when her math dropped terribly.

Recently, she hit high 90s cos she starts to have process skill....hahaha.That is why she insists that she must understand the method before she can accept it.I dont understand why this \"coin' type of question is always her blind spot.Is there a way to change the \"coin\"to something else as a question?


Cheers

Dharma:

Lynn2:

Hi Dharma,

Thank you for showing me another way in looking at this question.

Will walk thr the various methods that ksp has worked out and see whether she can see it.She believe in able to understand it rather than route learning.


Thanks.

No worries Lynn2.
Your girl definately has the right attitude towards learning. Good luck!

[tianzhu]

Lynn2:

I dont understand why this \"coin' type of question is always her blind spot.Is there a way to change the \"coin\"to something else as a question?

Hi

Instead of coins, you may use stamps or phone cards of different values.

How about trying on this questions about stamps?

Xie Ming Ming paid $36 for some 10 cents and 20 cents stamps. She bought 4 times as many 10 cents stamps as 20 cents stamps. How many stamps did she buy altogether?

In your question, the proportion of each type of coins are given, this simplifies the solution to a certain extent.

The concept of grouping or set is commonly used to solve such question. You may also use MD or Number* Value method. Although, the presentation may varies, but alternative solutions still hinge much on the proportion of coins.

Since your girl has difficulties on “coins question”, may I suggest you start with concrete objects or picture cut outs for the models. At home, use actual coins for illustration.

Then slowly proceed to using boxes or bars for the MD.

Hope this helps.

Best wishes.

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