cimman:

carol73:

Joan had some local and foreign post cards, The ratio of the number of her local post cards to the number of foreign post cards was 2:3. After she had given away 30 local post cards and 30 foreign post cards, the ratio of the number of local post cards to the number of foreign post cards became 5:9


1) how many local post cards did she have at first?
2)find the total number of foreign post cards she had left

I have given 2 method for solving the problem:
from the problem statement, you can see that there are 3 possible equations. Equation 3 is a derived equation, in that the values are not stated explicitly in the problem sum. Equation 3 is derived from Equation 1 and Equation 2.
In the first method, the solution uses the base equations that are given explicitly from the problem sum.
http://i42.tinypic.com/2ytp9qv.png\">

In the second method, equation 3 is utilized. The special property of equation 3 is that the Transfer value is 0. This leads to u = 4p. With an equation of this nature (where there are no whole numbers in the expression), solving a pair of simultaneous equation is easier using the Unit/Part equalization technique.
This concept is commonly called \"Common Difference\" because the Transfer values in the 2 columns are the same values. This in turn, leads to the outcome that the difference in the 2 Transfer values will give 0
(ie. -30 - (-30) = -30 + 30 = 0).

If the child is not able to recognize \"Common Difference\" concept from the problem statement, the table will lead the child to the concept.
http://i39.tinypic.com/2z9k0vl.png\">

It is important to understand that the second method is dependent on specific values in the Transfer box (ie. same values). If such values do not exist (ie. the Transfer values are different), then the 1st method is used, because the resultant 3rd equation will not provide any advantage in solving the simultaneous equation (ie. the resultant 3rd equation will have a whole number in the relationship, which is similar to the 1st 2 equations)

1 thing stands out in this qn:
the deduction for both types is the same(-30). since the deduction is the same, the difference will remain the same.

thus, before
L |-----|-----|
F |-----|-----|-----|

since difference remains the same and the difference in ratio of 5:9(after relationship) is 4units,
then at the beginning,
L = 4 x 2=8 units
F=4 x 3 = 12 units.
thus using either(I have decided to use the later),
12-9=3u
3u=30
1u=10.
at the end, foreign = 9u=90.

Musicstar:

Musicstar:

Can someone help me this question?


Dorothy and Rachel had some beads at first. Dorothy gave 1/6 of her beads to Rachel. Rachel then gave 2/5 of her beads to Dorothy. In the end, both of them had 180 beads each . How many beads did Rachel have at first?

Can someone please help me solve this question? Thank you very much.

from the end, we know that each has 180(also total is 180x2=360). since the transfer ended with Rachel giving 2/5 to Dorothy, thus Rachel has 3 units remaining.
therefore:

3u=180
1u=180/3=60.
Dorothy will have 60 before she receives 2/5 from Dorothy.
and since Dorothy gave 1/6 to Dorothy, means Dorothy's remaining is 5u(5/6)

therefore,
5U= 60
1u=12.
at the beginning, Dorothy has 12 x 6 = 72
Rachel =360-72=288

imp to help pupils understand that the remaining id Rachel is the same at the end and thus 3u=180.

cimman:

Niedino:

1. How is his comprehension skills? If he is facing difficulty in his reading comprehension, it might be that he is not understanding what the question requires him to do.

Niedino

yes, I too wondered about comprehension skills. How did he do for his English paper in Comprehension OE ?

if his English comprehension is alright, the next step would be to translate english to mathematical symbols. This is a skill that needs to be taught. For example, Tom was given $5 on top of his pocket money of $2. -> $2 + $5
It might seem very simple for us, but for someone not used to translating words to mathematical symbols, it is very confusing.

maths qn are direct opposite of English qn. there is nothing flowery abt the structure. every sentence gives info.

e,g

A and B has 120 eggs. After A gave B 10eggs, B has 3 times as much as A. How many eggs has A at the beginning?

Sentence 1: A and B has 120 eggs.
Data is given. total =120.

Sentence 2: After A gave B 10eggs, B has 3 times as much as A.
there was a transfer by A, and B will change too as B receives. The after relationship is B->3 units and A>1units.


B |-----|-----|-----|
A |-----|

since total unchanged, 1u = 120 /4 =30.
since A gave 10, then A will get back his 10 to return to 'before' state,
thus
A=30+10.

any qn that exhibits a relationship, a model can be drawn, that is the starting pt to solve the problem. Thus it is important that your child can recognise a relationship (trust me, most kids don't....and a lot of teachers don't too!)

a lot of p4 pupils draw model because they are expected to in schools. But MOST students DO NOT look at what they have drawn to solve the qn!

you need to ensure that ur child is looking at the model and knows how to use it as a representation to the problem.

All questions that can be solved with model can be solved using algebra… because both algebra n model are used to solve problems that exhibit relationship. algebra is abstract but models is visual.

you need to ensure that your child can see the relationship before they draw the model, otherwise the model will be a guesswork(or ur child may be able to draw it but cant understand it)

jwxh:

how to explain to my girl the following:


how many hundredths are there in 3.71?

tks

Check:

Does ur girl understand that:
1/100= 1part?
1=100/100=100parts?
If yes then 3= 1+1+1=100/100+100/100+100/100=300(wholes=300parts)
0.71=71/100 = 71(parts =71 parts)
Total=371(whole+parts)

Dandelion_Ivory:

I love going cycling with my family at East Cost Park.

2nd that. kids stay indoors all week long at grandma place, school etc. weekend is outdoors unless wet weather.

We bring our own bikes, cycle first. then tea break at macdonalds with fries and cakes and coffees.

then cycle again and look out for stretch of beach w lesser ppl and let them play sand.
i relax by drawing nonsense on the sand.

then dinner at some restaurant...decided by the kids...we just pay