Q&A - P3 Math

[small]

pertunia:

small:

Hassan has some pokemon cards to share among his friends. If he gives each friend 6 pokemon cards, he will have 5 cards left. If he gives each friend 8 pokemon cards, he will be short of 7 pokemon cards. How many pokemon cards does Hassan have? \t\t\t\t\t


Gap : 5+7 = 12

Different = 8 - 6 = 2\t\t\t\t\t\t\t\t
12 / 2 = 6 friends\t\t\t\t\t
\t\t\t
From red font :
6 cards x 6 + 5 cards
= 41 cards\t\t\t\t\t\t

Hassan have 41 pokemon cards altogether.

Hi small,

Can you please explain why you use gap = 5+7? I am missing something here. Thanks.

And thanks to all the others who help with the answers. Really appreciate it.

Hi pertunia,

I am using Inference Approach to solve this, learned this from my son. :oops:


Alternatively you can refer to Tianzhu's solution on other question. :celebrate:

http://www.kiasuparents.com/kiasu/forum/viewtopic.php?t=280&postdays=0&postorder=asc&start=2490

.

[usaik]

small:

Hi pertunia,

I am using Inference Approach to solve this, learned this from my son. :oops:

Hi Small,
Are inference approach taugth in school?
My child is able to solve this but too impatient to show me the detailed working :x . But I manage to conclude that he did it via the difference of the cards given to the friend and the difference of the cards left to deduce the no of friends. I am pretty sure this is a faster method compared to the traditional algebra method I was taught as the child is able to achive it mentally without any working rather quickly. But my concern is his lack of working may cause him to lose mark.


Hi Pertunia,
I can only achieve this via the algebra way which help me to understand how this gap thingy way works. If you were also trained in the way how I was trained perhaps this working might help you understand what the gap means.

No of friends : n
6n +5 = total number of cards........(1)
8n - 7= total number of cards ........(2)

(2) - (1) : 2n -7-5 = 0 => 2n = 7+5 => n = 6

No of cards Hassan has : 6x6 + 5 = 41

[bookwormkids]

Hi! Need help on the following question (Q35).


Karen had $40 more than Ali. After Karen bought a dress for $180 and Ali bought a tennis racket for $200, Karen had twice the amount of money Ali had. How much did Karen has at first?

Could anyone provide solution with model drawing please? (I don't really know how to draw the \"after\" diagram.) Thanks!

:oops:

[atutor2001]

bookwormkids:

Hi! Need help on the following question (Q35).


Karen had $40 more than Ali. After Karen bought a dress for $180 and Ali bought a tennis racket for $200, Karen had twice the amount of money Ali had. How much did Karen has at first?

Could anyone provide solution with model drawing please? (I don't really know how to draw the \"after\" diagram.) Thanks!

:oops:

Don't draw the BEFORE diagram first.

Draw the AFTER diagram first then add back $180 and $200 to this AFTER diagram such that Karen is longer than Ali (this \"longer\" part is $40) and we will get the comparison model for BEFORE.

[ ][ ]...Karen (AFTER)
[ ].......Ali (AFTER)

[ ][ ][-----$180--------]...Karen (BEFORE)
[ ][-------$200-----]$40 ....Ali (BEFORE)

So 1 UNIT is 200+40-180 = 60

[KSP]

P3 Maths question.


x + y = 500
x - y = 300

Find x and y.

How to explain the whole process of solving this to a P3? Thanks.

[atutor2001]

KSP:

P3 Maths question.


x + y = 500
x - y = 300

Find x and y.

How to explain the whole process of solving this to a P3? Thanks.

Hi KSP

Good question because many kids do not understand x-y in model. Draw x longer than y and the difference is 300. So x-y gives the \"difference\" in length of the model between X & Y where X is longer than Y. In words, (x-y=300) means X is 300 more than Y

[......................] ----X
[........]....300.... ----Y

[bookwormkids]

atutor2001:

bookwormkids:

Hi! Need help on the following question (Q35).


Karen had $40 more than Ali. After Karen bought a dress for $180 and Ali bought a tennis racket for $200, Karen had twice the amount of money Ali had. How much did Karen has at first?

Could anyone provide solution with model drawing please? (I don't really know how to draw the \"after\" diagram.) Thanks!

:oops:

Don't draw the BEFORE diagram first.

Draw the AFTER diagram first then add back $180 and $200 to this AFTER diagram such that Karen is longer than Ali (this \"longer\" part is $40) and we will get the comparison model for BEFORE.

[ ][ ]...Karen (AFTER)
[ ].......Ali (AFTER)

[ ][ ][-----$180--------]...Karen (BEFORE)
[ ][-------$200-----]$40 ....Ali (BEFORE)

So 1 UNIT is 200+40-180 = 60

Hi atutor2001! Thanks for your help!

[atutor2001]

bookwormkids:

Hi atutor2001! Thanks for your help!

You are most welcome. I find it easier to draw backwards from comparison model with \"complete unit\" then starting with \"difference\".

[Alex001]

Sorry, I originally written an item that was not related to the question. I apologize for this message.

[usaik]

Hi,

The following question is from one of the top school past year paper for P4. I need help on the way how working can be worked out for the question. Many thanks in advance please.

The answer provided is \"C\"

http://postimage.org/image/1p1t773s4/