"Supposedly" P3 Math Questions

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"Supposedly" P3 Math Questions

Postby AgonyMum » Tue Mar 06, 2012 11:05 am

Hi, can any brilliant mummies or educators help my child with these questions? I can solve some using "brain work" or by trial and error.Unfortunately,models MUST be used. Please enlighten.
Thanks so much!!

1.Sam is 40 years old. His son is 10 years old.How many years ago was Sam's age 6 times that of his son's?

2.John and Tim were selling cookies.In the beginning,John had 3 times s many cookies as Tim.After they had both sold 9 cookies,John had 5 times as many cookies as Tim.How many cookies did each of them have at first?

3.May just turned 7.She likes to dream about what she would be like when she grows up. " When I reach my mum's age,my mum will be 63 by then," she thought. Can you work out the age of May's mum?

4.A's money was 1/5 of B's money.When their mother gave them $10 each, A found that she has 1/3 of B's money. How much money did A have at first?

I really hate this so-called "models" method.I am just so clueless.....Please help,anyone?

AgonyMum
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Re: "Supposedly" P3 Math Questions

Postby MathIzzzFun » Tue Mar 06, 2012 11:50 am

AgonyMum wrote:Hi, can any brilliant mummies or educators help my child with these questions? I can solve some using "brain work" or by trial and error.Unfortunately,models MUST be used. Please enlighten.
Thanks so much!!

1.Sam is 40 years old. His son is 10 years old.How many years ago was Sam's age 6 times that of his son's?

2.John and Tim were selling cookies.In the beginning,John had 3 times s many cookies as Tim.After they had both sold 9 cookies,John had 5 times as many cookies as Tim.How many cookies did each of them have at first?

3.May just turned 7.She likes to dream about what she would be like when she grows up. " When I reach my mum's age,my mum will be 63 by then," she thought. Can you work out the age of May's mum?

4.A's money was 1/5 of B's money.When their mother gave them $10 each, A found that she has 1/3 of B's money. How much money did A have at first?

I really hate this so-called "models" method.I am just so clueless.....Please help,anyone?


Hi

"hate" is a strong word.

You can use the concept of "same gap/same difference" to solve all the questions.

1. Age difference will always remain the same.
2. If A has 20 more stamps than B, if A and B bought same number of stamps, the difference will still remain the same ie A will still have 20 more stamps than B. Similarly, if A and B gave away same number of stamps, the difference will also remain the same.

Here's the model for Q1...

Image

cheers.

MathIzzzFun
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Re: "Supposedly" P3 Math Questions

Postby MathIzzzFun » Tue Mar 06, 2012 12:10 pm

AgonyMum wrote:Hi, can any brilliant mummies or educators help my child with these questions? I can solve some using "brain work" or by trial and error.Unfortunately,models MUST be used. Please enlighten.
Thanks so much!!

2.John and Tim were selling cookies.In the beginning,John had 3 times s many cookies as Tim.After they had both sold 9 cookies,John had 5 times as many cookies as Tim.How many cookies did each of them have at first?



Hi

Q2.

Image

cheers.

MathIzzzFun
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Re: "Supposedly" P3 Math Questions

Postby MathIzzzFun » Tue Mar 06, 2012 12:27 pm

AgonyMum wrote:Hi, can any brilliant mummies or educators help my child with these questions? I can solve some using "brain work" or by trial and error.Unfortunately,models MUST be used. Please enlighten.
Thanks so much!!

3.May just turned 7.She likes to dream about what she would be like when she grows up. " When I reach my mum's age,my mum will be 63 by then," she thought. Can you work out the age of May's mum?


Hi

Q3.

Image

cheers.

MathIzzzFun
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Re: "Supposedly" P3 Math Questions

Postby MathIzzzFun » Tue Mar 06, 2012 12:48 pm

AgonyMum wrote:Hi, can any brilliant mummies or educators help my child with these questions? I can solve some using "brain work" or by trial and error.Unfortunately,models MUST be used. Please enlighten.
Thanks so much!!

4.A's money was 1/5 of B's money.When their mother gave them $10 each, A found that she has 1/3 of B's money. How much money did A have at first?



Hi

Q4.

Image

cheers.

MathIzzzFun
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Re: "Supposedly" P3 Math Questions

Postby AgonyMum » Tue Mar 06, 2012 1:43 pm

Hello MathIzzzFun,
First,I would like to thank you very,very much for responding and helping my child and I to solve the questions.And such beautiful presentations too :)

I have looked through your solutions and I think I understood them.Will be looking through them a couple more times to familiarise myself with the models before trying to "teach" my child.

It seems so easy when the solutions are right in front of you but when my kid and I attempted them,we either don't know how to start or we get stuck somewhere....

Are you a teacher or a professional educator of some sort?

I hope you can help us solve one more question -

Qn: 3 years ago,James was 9 times as old as his younger brother.4 years later, James would only be twice as old as his younger brother. How old is each of them now? (Models are required)

Many many thanks in advance!

AgonyMum
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Re: "Supposedly" P3 Math Questions

Postby AgonyMum » Tue Mar 06, 2012 2:05 pm

Hi,MathIzzzFun,
Regarding Q4,I understand your model but I cannot see why you equate 1 unit=$10. Is the green part ($10)=black part of 1 unit?
Thanks.

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Re: "Supposedly" P3 Math Questions

Postby tianzhu » Tue Mar 06, 2012 2:41 pm

AgonyMum wrote:Qn: 3 years ago,James was 9 times as old as his younger brother.4 years later, James would only be twice as old as his younger brother. How old is each of them now? (Models are required)

Hi

The difference in age between two people always stays the same.

The numbers in this question are not too big. P3 kids may also solve it with “Systematic Listing” as an alternate method to MD. It’s not too tedious in this particular instance.

As usual, I’ve drawn more MD than necessary to show the flow of events. Once kids are familiar with the logic behind the solution, they may consolidate the steps.

Hope this helps.

Best wishes.

Image

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Re: "Supposedly" P3 Math Questions

Postby MathIzzzFun » Tue Mar 06, 2012 2:56 pm

AgonyMum wrote:Hi,MathIzzzFun,
Regarding Q4,I understand your model but I cannot see why you equate 1 unit=$10. Is the green part ($10)=black part of 1 unit?
Thanks.


hi

I have added one more model ... 2 units = 1/3 of B and since the $10 + 1 unit = 1/3 of B, therefore 1 unit = $ 10

Image

cheers.
Last edited by MathIzzzFun on Tue Apr 24, 2012 10:34 am, edited 1 time in total.

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Re: "Supposedly" P3 Math Questions

Postby AgonyMum » Wed Mar 07, 2012 1:25 am

Hi tianzhu,thanks a lot for your step-by-step "model".Yes,I have understood it :)

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