Maths question - how to solve by model method?

[Mcf777]

chim ah! I Kee Qiu. Dont know how to answer.

 

BTW, i got A for my O level Math. Now, all math knowledge return back to the school.

[Mcf777]

bro, but for P3 standard, school wants them to use and write out the guess and check method which i had illustrate at post #4.

 

correct me if im wrong.

[Sosaria]

Try this Pri 5 question without using algebra or cross multiplication.

 

A and B has some money in the ratio of 13:8. After both of them gave away $133 each, the ratio of money becomes 4:1. How much money does A have at first?

 

NEXT QUESTION!!

 

Honestly, doing well in exams also depends on a bit of strategic planning. The kid must know not to be rattled psychologically by the one or two difficult question(s), and concentrate on getting those easy / manageable ones 100% correct, with no careless mistakes. Returning to those difficult question(s), do as much as possible and not just leave blank.

 

Still can score high grades, though may not be national top student

[Sosaria]

bro, but for P3 standard, school wants them to use and write out the guess and check method which i had illustrate at post #4.

 

correct me if im wrong.

 

Yes, I would think so, for lower primary. It's even easier for the kid to understand. As long as they can make a good choice in the initial values and know how to proceed from there on.

 

What I like about guess-and-check is that it is very methodical, i.e. you can teach the kid some simple steps to always apply to solve the question. Much like "rote learning".

 

What I don't like about it is the element of "guess", which I feel is not very mathematical...

[DarrenR10]

1 ST - 4ppl

1 RT - 6ppl

184pp == RT ? and ST ?

 

184 / 6 = 30.66

30x6 = 180pp

 

184 - 180 = 4ppl

 

So 30RT and 1ST. tio bio ??

[Quirky]

Assume that square or round table can hold only 4 people. So 40 tables hold 160 people.

There's a shortfall of 24 people, which can be made up only by people from round table.

Round table can actually hold 2 more people. So you would require 12 round tables. And thus, 28 square tables.

[Ender]

1 ST - 4ppl

1 RT - 6ppl

184pp == RT ? and ST ?

 

184 / 6 = 30.66

30x6 = 180pp

 

184 - 180 = 4ppl

 

So 30RT and 1ST. tio bio ??

think you have to stay back after class.

[Ronleech]

Try this Pri 5 question without using algebra or cross multiplication.

 

A and B has some money in the ratio of 13:8. After both of them gave away $133 each, the ratio of money becomes 4:1. How much money does A have at first?

 

Any one got the answe for this?

[Raymondism]

Try this Pri 5 question without using algebra or cross multiplication.

 

A and B has some money in the ratio of 13:8. After both of them gave away $133 each, the ratio of money becomes 4:1. How much money does A have at first?

 

 

skip... try another question... LOL

[Quirky]

Since both gave out $133 equally, the difference between A and B stays the same.

 

BEFORE - 13:8 (Diff of 5 units)

AFTER - 4:1 (Diff of 3 units)

 

5 units in the previous ratio equal 3 units in the new ratio.

So you could try finding a common multiple for the diff. Let's use 15.

 

So 13:8 -> 39:24 (Diff of 15)

4:1 -> 20:5 (Diff of 15)

 

39 - 20 units is 19 units which is 133. So 39 units is 273. 24units is 168.

 

[Sosaria]

Since both gave out $133 equally, the difference between A and B stays the same.

 

BEFORE - 13:8 (Diff of 5 units)

AFTER - 4:1 (Diff of 3 units)

 

5 units in the previous ratio equal 3 units in the new ratio.

...

 

Brilliant! I reached the above step, then got confused on how to solve it without resorting to cross-multiplication.

 

Looks like I "fail" P5, got to go back to primary school

[Ronleech]

Brilliant! I reached the above step, then got confused on how to solve it without resorting to cross-multiplication.

 

Looks like I "fail" P5, got to go back to primary school

i also stuck there...try to use model or cannot get any clue to go on...

[Rayleigh]