Q&A - P4 Math

[kiasuMay11]

PiggyLalala:

mrskoo123:

Hi need help on following qns:


Alvin paid $26 for 4 books and 3 pens.
John paid $1 less than Alvin for 3 books and 5 pens.
What was the total cost for 1 book and 1 pen?

thanks in advance

4 books and 3 pens - 26
3 books and 5 pens + $1 - 26
Therefore the price of 1 book is equivalent to 2 pens + $1
4 books is equivalent to 8 pens + $4
Therefore 11 pens -$26 -$4 =$22
1 pen - $2 and 1 book - $5
1 pen and 1 book cost $7

I understand. But how to explain to a P4?

[24hr-mum]

why is it +$1 and not -$1? i thot john paid $1 less?

[PiggyLalala]

Because the value of 3 books and 5 pens = $25

the value of 4 books and 3 pens = $ 26.
That is, if you buy one less book, you can get 2 more pens and $1, hence,
the value of 1 book = 2 pens + $1

[MathIzzzFun]

mrskoo123:

Hi need help on following qns:


Alvin paid $26 for 4 books and 3 pens.
John paid $1 less than Alvin for 3 books and 5 pens.
What was the total cost for 1 book and 1 pen?

thanks in advance

Hi

grouping concept in pictorial...

http://i45.tinypic.com/fnwxub.png\">

cheers.

[24hr-mum]

MathIzzzFun, that’s a great way. How did u get the idea of duplicating the 4book+3pen equation?

[24hr-mum]

stimes i find it ridiculous that sch are setting questions that the child cant do and even parents stimes are intimidated…, and its just primary questions. sigh…

[MathIzzzFun]

24hr-mum:

MathIzzzFun, that's a great way. How did u get the idea of duplicating the 4book+3pen equation?

Using same gap concept, 5pens 3books -- gap of 2, 4 books 3pens -- gap of 1, so double 4 books +3pens to get gap of 2.

cheers.

[PiggyLalala]

MathIzzzFun:

24hr-mum:

MathIzzzFun, that's a great way. How did u get the idea of duplicating the 4book+3pen equation?

Using same gap concept, 5pens 3books -- gap of 2, 4 books 3pens -- gap of 1, so double 4 books +3pens to get gap of 2.

cheers.

:thankyou: learn something new again.
U are a great Maths teacher.

[Jamesbond]

http://i50.tinypic.com/wu5dog.jpg\">


Pl help.... :scared:

[Jamesbond]

PiggyLalala:

MathIzzzFun:

[quote=\"24hr-mum\"]MathIzzzFun, that's a great way. How did u get the idea of duplicating the 4book+3pen equation?

Using same gap concept, 5pens 3books -- gap of 2, 4 books 3pens -- gap of 1, so double 4 books +3pens to get gap of 2.

cheers.

:thankyou: learn something new again.
U are a great Maths teacher. :)[/quote]MathIzzzFun U r really great...I did learn this method now.... :rahrah: