Q&A - P4 Math

[Nebbermind]

They have the same methods? Didn’t compare. Just bought n found it quite comprehensive.

[cimman]

snowball:

There were twice as many men as women in the hall.

After 12 women had left the hall, there were thrice as many men as women who remained in the hall.
How many men were in the hall at first?

here's another way of looking at the problem. I use the Table Heuristics approach. You first start off with this table:
http://i47.tinypic.com/73o6lu.png\">

As you read the question, you plug the values into the table:

There were twice as many men as women in the hall.
http://i49.tinypic.com/2u7ak4x.png\">

After 12 women had left the hall,
http://i50.tinypic.com/2cxuadd.png\">

there were thrice as many men as women who remained in the hall.
http://i50.tinypic.com/11gu05h.png\">

since no mention was made of Men leaving the hall, we can assume that no men left the hall, thus
http://i50.tinypic.com/33azz8x.png\">

this is what I call a Transfer type problem. They all share this same formula: Before + Transfer = After, circle the equations:
http://i48.tinypic.com/vhuykn.png\">

alternatively, this is what you can do to avoid simultaneous equations:
http://i46.tinypic.com/34o351e.png\">
since 2u = 3p, we use the common multiple technique to make u = p
(x3) 2u = 3p (x2)
6u = 6p,
thus u = p


of course, in normal working, just show the last table will do.
Using this technique will help you solve very complex problems, all the way up to 5 marks PSLE type problems.
I call this Just In Time (JIT) Processing. As you read a sentence, you plug in the values, there's no need to read the entire problem and process all the relationships mentally.
I conduct workshop for parents to learn this technique. http://www.kiasuparents.com/kiasu/forum/viewtopic.php?f=43&t=32278. It's a free workshop.

[cimman]

The solution presented using Modelling (as presented by BigDevil) and the solution presented here are basically the same. The approach, however is different.

In the modelling solution (by BigDevil), you will find that drawing a model of 6 units will allow the 2 rows of boxes to equate to each other. It is this crucial part that stumps most students, ie. how to draw the boxes so that the 2 rows equate ?

here is where Table Heuristics and Modelling says the same thing:
(x3) 2u = 3p (x2)
......6u = 6p

once we have this relationship worked out (ie. how to equate the u and the p), solving the other relationship (the part where 12 is present) is straight forward.

[Nebbermind]

Actually they are all some form of simultaneous equation, incl dwg models…the diff being when u substitute/replace the unknowns.


My advise to the younger ones and the not too math savvy to STAY on one method until you are proficiency in it.

Juz my 2cents

[violet04]

Hi,

Need advice of the following question:

6 pupils are standing in a circle during a Physical Education lesson. Each pupil is allowed to throw the ball to another pupil only once. What is the maximum number of throws that can be made?

1) 12
2) 13
3) 14
4) 15

The answer key said the answer is option (4). Why? :imdrowning:

[CloudeeDaz]

violet04:

Hi,

Need advice of the following question:

6 pupils are standing in a circle during a Physical Education lesson. Each pupil is allowed to throw the ball to another pupil only once. What is the maximum number of throws that can be made?

1) 12
2) 13
3) 14
4) 15

The answer key said the answer is option (4). Why? :imdrowning:

pupil 6 throws to pupil 1, 2, 3, 4, 5
pupil 1 ---------------- 2. 3, 4, 5
pupil 2 ---------------- 3, 4, 5
pupil 3 ---------------- 4, 5
pupil 4 ---------------- 5

total--------------------------------15

[snowball]

pr 4 - Fraction


1) Esther had $350 more than Kevin. Ester spent 3/4 of her money & Kevin spent 4/7 of his money. In the end, Kevin & Esther had the same amout of money left. Find the amout of money Kevin had at first.

2)At the graduation ceremony, there were 30 less boys than girls.After 3/5 of the boys & 5/8 of the girls had left the hall for recess, there was an equal number of boys & girls that remained behind. Find the number of boys who were presented at the graduation ceremony at first.

TIA

[pchong]

snowball:

pchong:

I have seen a number of posts here asking for maths solution....ur dc are still busy practicing on maths problems even after exam? I can't get mine to do any work as he said now is holiday season, suppose for him to rest and relax.

Is indeed and actually very difficult for them to do revision during the\" post exam period \" :stompfeet:

So, pchong, if your dc is already >85 in her pr 4 sa2, i think u can relax a bit bit la :please:

No, instead he scored <80 in his SA2, but I can't get him to start off with his revision...his heart is not there! Can anyone advise what can I do?

[HAPPYH]

pchong:

snowball:

[quote=\"pchong\"]I have seen a number of posts here asking for maths solution....ur dc are still busy practicing on maths problems even after exam? I can't get mine to do any work as he said now is holiday season, suppose for him to rest and relax.

Is indeed and actually very difficult for them to do revision during the\" post exam period \" :stompfeet:

So, pchong, if your dc is already >85 in her pr 4 sa2, i think u can relax a bit bit la :please:

No, instead he scored <80 in his SA2, but I can't get him to start off with his revision...his heart is not there! Can anyone advise what can I do?[/quote]Show him the KSP site. Then he will understand

I told my DD to start focusing from December second week (after our 2.5 weeks vacation). She already complians that it is too boring and not sure what to do. I simply said \"read storybooks' She gave me a look and kept quiet .

[snowball]

Nebbermind:

[

quote]
This is one book you should buy
http://edu.marshallcavendish.com/Storage/CoverImageFile/9789810195649.jpg\">

:thankyou: Nebbermind, I'll surely take a look at it :please: