Q&A - P3 Math

[Champion]

CoffeeCat:

Hi, model drawings is a method that can be used to solve many problems for Singapore's PSLE Maths. However if large numbers are involved \"better methods\" (but based on the same principle) are used sometimes. So yes, it's probably a must for moving to upper primary maths (but some may argue otherwise :scared: )
Math Heuristics are essentially a set of techniques used to solve questions. I believe there is a thin assessment book called Problem-Solving with Heuristics.
Model Drawing can be seen as a heuristic too.
Quoted from moe maths syllabus
\"Thinking skills and heuristics
Students should use various thinking skills and heuristics to help them solve mathematical problems. Thinking skills are skills that can be used in a thinking process, such as classifying, comparing, sequencing, analysing parts and wholes, identifying patterns and relationships, induction, deduction and spatial visualisation. Some examples of heuristics are listed below and grouped in four categories according to how they are used:
•
To give a representation,
e.g. draw a diagram, make a list, use equations
•
To make a calculated guess,
e.g. guess and check, look for patterns, make suppositions
•
To go through the process,
e.g. act it out, work backwards, before-after
•
To change the problem,
e.g. restate the problem, simplify the problem, solve part of the problem\"

Hi coffeecat,
Thanks so much for the clarification; understands better now :hi5:

Guess I have to read up / to do this coming June holiday lioa :imcool:

[CoffeeCat]

Champion:

Hi coffeecat,
Thanks so much for the clarification; understands better now :hi5:

Guess I have to read up / to do this coming June holiday lioa :imcool:

Opps, the assessment book I talking about is \"Use of heuristics in problem solving\".

[Gin]

Hi, hope someone can help me out here:


There were two times as many blue clips as there are yellow clips. After giving away 66 blue clips and 8 yellow clips, there were thrice as many yellow clips as there were blue clips. How many clips were there at first?

Thanks

[MathIzzzFun]

Gin:

Hi, hope someone can help me out here:


There were two times as many blue clips as there are yellow clips. After giving away 66 blue clips and 8 yellow clips, there were thrice as many yellow clips as there were blue clips. How many clips were there at first?

Thanks

Hi

Hope this helps - http://www.flickr.com/photos/62167097@N02/5739515389/in/photostream

cheers.

[yingxuan0806]

Gin:

Hi, hope someone can help me out here:


There were two times as many blue clips as there are yellow clips. After giving away 66 blue clips and 8 yellow clips, there were thrice as many yellow clips as there were blue clips. How many clips were there at first?

Thanks

-units n parts method

Before After
Blue 2u 2u-66 = 1p
Yellow 1u 1u-8 = 3p

to make them the same
3p = 6u-198
6u-198 = 1u-8
shifting:
6u-1u = 198-8
5u=190
1u=190/5=38
3u=38x3=114

hope you understand.

[Gin]

Thank you, yingxuan0806 and MathIzzzfun!

[mama_10]

Nd help !


The length of a rectangle table is 3times its width. If the length was 2m shorter and the width, 80cm wider, a square table would be formed. What are the dimensions of the rectangler table?

Thanks!

[davos]

Let the width be 1 unit, the length 3 units, The length is longer than the width by 2 units.

If the width is increased by 80cm, length is decreased by 200cm,
80 + 200=280—>2 units,
thus 1 unit is 280/2 =140.
Width is 140cm, length is 140 x 3 = 420cm.

[mama_10]

davos:

Let the width be 1 unit, the length 3 units, The length is longer than the width by 2 units.

If the width is increased by 80cm, length is decreased by 200cm,
80 + 200=280--->2 units,
thus 1 unit is 280/2 =140.
Width is 140cm, length is 140 x 3 = 420cm.

Im using the method below to find out the answer :-
3x-200=x+80
2x=280
x=140
L=3x=420cm
Can you explain why 80+200-->2 units?

Thanks

[ChiefKiasu]

mama_10:

davos:

Let the width be 1 unit, the length 3 units, The length is longer than the width by 2 units.

If the width is increased by 80cm, length is decreased by 200cm,
80 + 200=280--->2 units,
thus 1 unit is 280/2 =140.
Width is 140cm, length is 140 x 3 = 420cm.

Im using the method below to find out the answer :-
3x-200=x+80
2x=280
x=140
L=3x=420cm
Can you explain why 80+200-->2 units?

Thanks

80+200 represents the total difference in length between the current length and breadth of the rectangle.
Since length = u + u + u and width = u, the difference in length is 2u.
So 2u = 80+200