Q&A - P5 Math

[Udon]

tianzhu:

Udon:

Thanks for the reply, but i do not understand how to calculate

Kenny....1 unit become 4 units
Sally......2 units become 8 units

Hi

Good Morning.

P5 students should be comfortable with changing from decimals to fractions and ratios.

1.4 ------ 14/10 ------- 7/5

A student should note that the total number of units stays the same in the various scenarios. Perhaps a good way is understand is to imagine Kenny and Sarah inside a box. The exchanges between them take place inside the box. Nothing flows out of the box, hence the total number of pens they had stays the same.

I’ve attempted to show the flow of events in this slide, as you can see nothing more than equivalent ratios is required to solve this question.

Hope this helps.

Best wishes

http://farm8.staticflickr.com/7232/7218581850_f5c8b8288e_z.jpg\">

Thankz for the clear illustration, I & my girl can understand better now. :))

[Udon]

highanxiety:

Hi Udon

You might want to take note that they make used of constant total concept in before and after situation to solve, using LCM of 12, 4 and 3 is 12.

Hi..Hi

Thanks for highlighting the concept....

[TulipisPink]

Thank you very much to all who has help in showing the lights in maths question.


You are the best !

Thanks again.

[MathIzzzFun]

NewMum2012:

http://i49.tinypic.com/b3wlqf.jpg\"> Hi Can anyone please help with this Question?

Hi

area of triangle PRV + area of triangle QSV
= 1/2 area of rectangle PQRS
= unshaded area + area of quadrilateral TUVW
I think you can complete the solution from here

cheers.

[CoffeeCat]

NewMum2012:

You quoted \"area of triangle PRV + area of triangle QSV

= 1/2 area of rectangle PQRS\"

Can you please explain how this is possible?

Thanks for your prompt response!

area of PRV = 1/2 * PS* PV
area of QSV = 1/2 * PS* VQ
area of PRV + QSV = 1/2 * PS * (PV+VQ) = 1/2 * PS *PQ

This looks like a maths olympiad question...

[MathIzzzFun]

NewMum2012:

You quoted \"area of triangle PRV + area of triangle QSV

= 1/2 area of rectangle PQRS\"

Can you please explain how this is possible?

Thanks for your prompt response!

Hi
Area of triangle PVR =area of triangle PVS (same base PV & same height PS=QR)
Area of triangle PVS + area of triangle QVS= 1/2 area of rectangle PQRS
so, area of triangle PVR + area of triangle QVS = 1/2 area of rectangle PQRS

cheers.

[cimman]

this question has been answered before:

http://www.kiasuparents.com/kiasu/forum/viewtopic.php?f=71&t=6373&start=740

quite some time ago, that is.

[cimman]

this question was answered before:

http://www.kiasuparents.com/kiasu/forum/viewtopic.php?f=71&t=6373&start=740

you should try the other question (the double square question) as well. it's also an interesting question.

[happyheart]

Hi, can someone help with this question please?


Jason and Muthu had some cards. During a game, Jason lost 1/4 of his cards to Muthu in the first round. In the second round, Muthu lost 1/3 of his cards to Jason. In the third round, Jason lost 1/6 of his cards to Muthu. At the end of the three rounds, Jason had 420 cards and Muthu had 744 cards left respectively. How many cards did Jason have at first?

Thank you.

[tianzhu]

happyheart:

Hi, can someone help with this question please?


Jason and Muthu had some cards. During a game, Jason lost 1/4 of his cards to Muthu in the first round. In the second round, Muthu lost 1/3 of his cards to Jason. In the third round, Jason lost 1/6 of his cards to Muthu. At the end of the three rounds, Jason had 420 cards and Muthu had 744 cards left respectively. How many cards did Jason have at first?

Thank you.

Hi

In working out this question, one key point to take note is that the number of cards stays the same throughout.

Work backwards.

5 units (5/6) ------ 420

1 unit ------ 84

6 units (6/6) ------- 504

You may continue with the rest of the calculations.

Hope this helps.

Best wishes

http://farm8.staticflickr.com/7236/7344390536_69246f67b8_z.jpg\">