Q&A - P4 Math

[tianzhu]

Breadandmuffins:

Ds 's teacher uses the on sponge method called \"number of units and value of units\". He asked me when should he use this method cos he thinks it's possible to use guess and check too. Is there any way to tell? Do youthink model can be used here?

Hi

Good Morning.

MD is one of the many problem solving heuristics in primary school maths syllabus. It’s not the only one.

While a picture might help some students to see maths better, it is not necessary to have visual representations for all answers especially when students are able to make connections without it.

A neat way to solve your question is to use “Grouping concept”.\t

If I am not wrong “Number*Value” method also uses the mechanics of “Grouping Concept” but it is presented in tabulated form.

Lower primary kids may also use GC. While using GC, it’s important not to do it in a haphazard way, try to present it in a logical way with calculated guesses.

Best wishes

[Breadandmuffins]

THank you everyone. Will continue to learn . Just last nite, I was cracking my head over some more questions to help DS revise for his SA1.


Hi Optimistforum, that qn is taken from the Onsponge book which DS used in school. I had a hard time trying to figure out as well. See stars every nite.

[teh_oh]

atutor2001:

ozora:

need help:

1)2 similar shirts cost $26 more than 3 pairs of shoes. If their total cost is $158. find the cost of 1 shirt.

2) shop A had 164 more customers than shop B.
after 1/4 of the customers in shop A went to shop B. there were 48 more customers in shop B than shop A.
How many customers were there in shop A and shop B now?

Algebra is the easier way. Anyway, if you wish to solve it using logical thinking, a possible way is as follows :

A is 164 more than B.
To make A and B equal, 164/2 = 82 must move from A to B
To make B more than A by 48, another 48/2 = 24 must move from A to B
(common mistake is in forgetting to divide by 2)

So a total of 82 + 24 = 106 must move from A to B so that B will be 48 more than A.

This 106 is 1/4 of the original number in A.

So the original number in A is 4 quarters, that is 106 x 4 = 424
So the original number in B is 424 - 164 = 260

The number in A now is 424 - 106 = 318
or
The number in A now is 3/4 of the original 3/4 x 424 = 318

The number in B now is 260 + 106 = 366

Personally I don't recommended this way to solve. Too much thinking needed.

Hi atutor2001,

My child's working is as follows:
164 - 48=116
116 divide 2 = 58
58 + 48 = 106
1/4 --> 106
4/4 - 1/4 = 3/4
106 x 3 = 318 (Shop A)
318 + 48 = 366 (Shop B)

Is my child's workings acceptable?

Thank you.

[24hr-mum]

small:

24hr-mum:

for qn such as: if the teacher shares her sweets wf 5 pupils she wil hv 3 sweets left, if she share wf 6 pupils she wil b short of 7 sweets, how many sweet she has?any shortcut besides listg the multiples of 5 n 6? the clue gvn is she has more than 40 sweets

Hi 24hr-mum,

HTH...

As the number of sweets in both cases is the same thus the answer is 53 sweets.

Case 1: 5 students with extra of 3 sweets
Case 2: 6 students with short of 7 sweets



my gal math teacher say conceptuallu wrong to say 1 student has 10 sweets

5 students + 3 sweets = 6 students - 7 sweets
1 student = 10 sweets

From case 1 ------(5x10 )+3 = 53 sweets

[sunshine0809]

http://i49.tinypic.com/5k3nyh.jpg\">

Ans 146

[Sharmum]

Hi,


May i know if theres a shorter method?

:?

http://i50.tinypic.com/dfehhg.jpg\">

[small]

small:

24hr-mum:

for qn such as: if the teacher shares her sweets wf 5 pupils she wil hv 3 sweets left, if she share wf 6 pupils she wil b short of 7 sweets, how many sweet she has?any shortcut besides listg the multiples of 5 n 6? the clue gvn is she has more than 40 sweets

Hi 24hr-mum,

HTH...

As the number of sweets in both cases is the same thus the answer is 53 sweets.

Case 1: 5 students with extra of 3 sweets
Case 2: 6 students with short of 7 sweets

24hr-mum:

my gal math teacher say conceptuallu wrong to say 1 student has 10 sweets

5 students + 3 sweets = 6 students - 7 sweets
1 student = 10 sweets

From case 1 ------(5x10 )+3 = 53 sweets

Hi 24hr-mum,

Pictorial diagram will be easier to understand.

http://i50.tinypic.com/9an6v6.jpg\">

[small]

Sharmum:

Hi,


May i know if theres a shorter method?

:?

http://i50.tinypic.com/dfehhg.jpg\">

Hi Sharmum,

Please refer to attached pic, HTH.

http://i48.tinypic.com/2llecjs.jpg\">

[Jamesbond]

A set of two blouses costs $41. Ivy found out that she could only buy 4 blouses but not more than 6 blouses with the amount of money she had. What is the possible amount of money she had?

1) $50 2) $90
3) $150 4) $250

Answer is option 2.

Pl explain me this in detailllll....VVVVV urgent......I donno..... :yikes:

[Champion]

Jamesbond:

A set of two blouses costs $41. Ivy found out that she could only buy 4 blouses but not more than 6 blouses with the amount of money she had. What is the possible amount of money she had?

1) $50 2) $90
3) $150 4) $250

Answer is option 2.

Pl explain me this in detailllll....VVVVV urgent......I donno..... :yikes:

P4 dd1 answer: 2 blouses $41 then 4 blouses will be $41 x 2 = $84. Therefore $84 nearest is $90; Answer (2).