Q&A - P3 Math

[Thein]

cimman:

this is the LCM (lowest common multiple) method. There will always be a number of matching common multiples. Always pick the lowest one, unless the question qualifies the range, ie. 50 to 60.

Hi cimman
Thank you.

for this problem..does it work?

Mother has some money to buy beef. She will have $15 left if she buys 3kg of beef. However, she will need $3 more if she wants to buy 4kg of beef instead. How much money does Mother have?

sorry to trouble....

Thank you once again.

Hi Tianzhu
i could understand the model. but how to differentiate the problems by reading them.
awaiting for your answer.

Thank you MathIzzFun...not able to get you

[tianzhu]

Thein:

Hi Tianzhu


I need a help.

First, I should thank you for I was able to understand model drawing only with your explanations. Thanks a lot.

i've taught my child, model drawing to solve problems like :
Mrs. Tay has a bag of sweets. If she gives each child 7 sweets, she will be left with 5 sweets. If she gives each child 9 sweets, she will need 5 more sweets.
a) How many children are there?
b) How many sweets are there?

but for this problem:

Mrs. Raju bought a sack of rice which weighed less than 50kg. If she packed the rice into bags of 5kg each, she would have 3kg of rice left. If she packed it into bags of 7kg each, she would have 4kg of rice left. How many kg of rice did Mrs. Raju buy?

i couldn't draw the model.

i've to go for another heuristic approach. finding the multiples....

i don't know how to differentiate the problems...or is there any common method that i can teach my kid...

Thank you in advance.

Hi

First thing first, I’ve to begin by saying that I am not a trained educator, I am a daddy.

So I can only share with you some of my experiences I’ve had in my kid’s PSLE journey. They are entirely my own and may not be always correct.

The common method used by primary students to solve the questions on Mrs Tay and Mrs Raju is “Systematic Listing”. Students usually present their solutions in tabulated list with “Multiples Method’ or MM. This method may be tedious, but is good for less mathematically inclined students. As long as students are careful in their calculations, three or four marks are safe in their bags.

Well, we are in Singapore, where “cheaper, faster and better” is a way of life. That’s why life is stressful.

We are always looking for faster and better method.

You’ll realise that Mrs Tay question can be solved more efficiently using “Gap and Difference” concept.Some may call it \"Excess and Shortage\"

You’ll also realise that the same concept cannot be applied to the Mrs Raju question.

Why?

In Mrs Tay question, the number of children and number of sweets is a fixed number. While in Mrs Raju question, the number of bags is different in the two cases or scenarios.

In GD type of questions, the question usually asks students to find out the number of children/boxes as a part of the question.

In Raju types of questions, usually one is given a range of numbers and asked to find a number within the ranges or is asked to find the lowest possible number.

Observe the two questions and note the differences.

Best wishes

[Thein]

Hi Tianzhu


Thank you so much for all your efforts.
:salute:

[tianzhu]

Hi Champion


Only have time to take 1 question, I’ll Q3.

For P3 students, it’s usual to use Guess and Check or Trial and error as the numbers are neat and small.

If you’re looking for alternatives, you may use “Make a Supposition” or you may call it the “Pretend Pretend lah” method.

You begin by “Assume or pretend that there were 18 cow.”

Best wishes

http://farm6.static.flickr.com/5106/5685781848_d7f9b8381a_z.jpg\">

[tianzhu]

Thein:

Hi Tianzhu


Thank you so much for all your efforts.
:salute:

Hi Thein

You're welcome.

Best wishes

[Champion]

tianzhu:

Hi Champion


Only have time to take 1 question, I’ll Q3.

For P3 students, it’s usual to use Guess and Check or Trial and error as the numbers are neat and small.

If you’re looking for alternatives, you may use “Make a Supposition” or you may call it the “Pretend Pretend lah” method.

You begin by “Assume or pretend that there were 18 cow.”

Best wishes

http://farm6.static.flickr.com/5106/5685781848_d7f9b8381a_z.jpg\">

Hi Tianzhu,
Thanks so much for your help :celebrate: . Your model example is very clear - wondering how can I download or print out those model answers from this forum? Can anyone helps? :thankyou:

[tianzhu]

Champion:

Hi Tianzhu,
Thanks so much for your help :celebrate: . Your model example is very clear - wondering how can I download or print out those model answers from this forum? Can anyone helps? :thankyou:

Hi

You're welcome.

Place your mouse pointer at the image, do a right click at the mouse,you may choose to save picture, print picture or copy.

Best wishes

[corneyAmber]

http://i56.tinypic.com/29xhgnm.jpg\">

[corneyAmber]

http://i53.tinypic.com/11ramo3.jpg\">

[teh_oh]

ksi:

http://i56.tinypic.com/29xhgnm.jpg\">

Hi ksi,
Thanks for the model. The working can be simplifed as follows:-

5u = 125-80=45
u=45/5=9
Therefore T=80-9=71