Q&A - PSLE Math

[small]

Hi tianzhu , thanks for the solution.



(80*15)/10 which is same as 8U = 8 * 15 = 120.

[mHeu]

check out http://unittransfermethod.blogspot.com

i think they have similar questions there with an alternative way to solve it...logical, systematic and neat, based on the fundamentals of ratio. nice

[tianzhu]

More P6 questions from CNA forum.You may go to this site.

( http://www.channelnewsasia.com/discussion/forum.htm )

1. Courier A takes 10 hours to deliver a parcel from Town X to Town Y. Courier B takes 12 hours to deliver the parcel along the same route. If the speed of Courier A is 9km/h faster than that of Courier B, find the speed of Courier A.

2. There were some apples at a fruit stall. In the morning, the number of apples sold was 2/5 of the apples left. In the afternoon, another 44 apples were sold. The total number of apples sold was 6 less than 9/14 of the number of apples the fruit stall had at first. How many apples were there at first?

3. In a grooming workshop organised by the school, 75% of the pupils participated were girls. 49 girls and 3 boys quitted halfway and went home. The remaining pupils were organised into groups of 10 for group discussion. There were 3 boys in each group. How many pupils participated in the grooming workshop at first?

4. There were some apples and oranges in a box. 80% of the fruits in the box were apples. Ali sold 63 apples and 9 oranges. He packed the remaining fruits into packets of 12 apples and oranges. Each packet of fruits has 3 oranges. Find the total number of oranges Ali had at first.

5. When Mrs Lee was 40 years old, her son was twice her daughter's age. Mrs Lee will be twice her son's age when her daughter is 28 years old. How old will Mrs Lee be when her daughter is 20 years old?

6. In a concert, 75% of the audience were female. 75 females and 5 males left the concert half way. The remaining audience were allocated seats in groups of 10. Each group has 3 males. How many people were in the audience at first?

7. Tom wants to complete a jigsaw puzzle. On the first day, he fitted 20% of the puzzle. On the second day he fitted another 60 pieces. The ratio of fitted to non-fitted pieces is now 2:5. How many pieces are there in the jigsaw puzzle?

8. Shop X sells a watch for $2400 which is 25% less than what Shop Y sells. During a sale, both shops offer an equal percentage discount. Mr Lee bought the watch in Shop Y and paid $520 more than the discounted price in Shop X. What is the percentage discount given by both shops?

9. The ratio of Ryan's pocket money to John's pocket money was 3 : 2. After Ryan saved $15 and John spent $8, the ratio of Ryan's pocket money to John's pocket money was 3 : 1. How much money did Ryan have at first?

[tianzhu]

BlissMom:

Hi Small, c below attempt to explain how to arrive at

30u= 20u+600+900. See if it helps? I prefer this approach which is less lengthy and once the child get the concept, he could work to the solution in shorter steps... at least it worked for my kids


http://www.postimage.org/image.php?v=aV9XQL9

Hi
I remembered seeing this method in a Maths book by Ammiel Wan.

[BlissMom]

Yes, it's from a book that has Ammiel Wan as one of the authors. It's called ThinkingMath@onSponge Conquer Problem Sums.


My daughter's school had all the P3 to P6 buy the book so I have no choice but to look at it while teaching her. Actually, I like it not just because it has really challenging questions but it also provides other strategies which i never knew existed. The strategies I learnt are very helpful in solving problems which I always find model drawing hard to apply. Many parents I spoke to felt the same way too. But it's funny, the books are not sold at Popular and you can only buy online through this site http://www.onsponge.com. Check it out if interested because that website also have the sample chapters and strategies taught in the book.

[tianzhu]

BlissMom:

Yes, it's from a book that has Ammiel Wan as one of the authors. It's called ThinkingMath@onSponge Conquer Problem Sums.


My daughter's school had all the P3 to P6 buy the book so I have no choice but to look at it while teaching her. Actually, I like it not just because it has really challenging questions but it also provides other strategies which i never knew existed. The strategies I learnt are very helpful in solving problems which I always find model drawing hard to apply. Many parents I spoke to felt the same way too. But it's funny, the books are not sold at Popular and you can only buy online through this site http://www.onsponge.com. Check it out if interested because that website also have the sample chapters and strategies taught in the book.

Hi
The book I am referring to is Challenging Maths Problems made easy by Ammiel Wan.It's available in Popular Bookstore.Problems involving external transfer with two changed quantities can also be solved by Model Drawing.But, my son is not motivated to learn both methods.He prefers to use Ammiel's way.I leave it to him, afterall, he'll be taking the PSLE exam.

[small]

Hi all,


Thanks for your time. Beside using algebra, is there any other method to solve this question?
:oops:
[quote]Question:

A had 240 cards and B had 360 cards at first.
After selling an equal number of cards, the number of cards B had left to number of cards A had left was 1 :3.
How many cards did each of them sell?[/quote]If x = number of cards sold

=> (240-x) / (360-x) = 1 / 3
=> 3 (240-x) = 360-x
=> 720-3x = 360-x
=> 2x = 360
=> x = 180

Each of them sold 180 cards.

[tianzhu]

[quote]Question:


A had 240 cards and B had 360 cards at first.
After selling an equal number of cards, the number of cards B had left to number of cards A had left was 1 :3.
How many cards did each of them sell?[/quote]Hi
The ratio of B:A should be 3:1 instead of 1:3.
After selling an equal number of cards, the number of cards B had left to number of cards A had left was 3:1.

Hope this helps.
http://farm4.static.flickr.com/3352/3343740901_ddeff048a6_o.jpg\">

[small]

tianzhu:

[quote]Question:


A had 240 cards and B had 360 cards at first.
After selling an equal number of cards, the number of cards A had left to number of cards B had left was 1 :3.
How many cards did each of them sell?

Hi
The ratio of B:A should be 3:1 instead of 1:3.
After selling an equal number of cards, the number of cards B had left to number of cards A had left was 3:1.

Hope this helps.
http://farm4.static.flickr.com/3352/3343740901_ddeff048a6_o.jpg\">[/quote]Hi Tianzhu,

Sorry for the typo and many thanks for your solution.

[tianzhu]

The Singapore Model Method for Learning Mathematics


I stumbled into this book while browsing in Popular bookstore. It is very readable with colourful models and has about 135 pages. It is published by EPB Panpac Education. It offers a comprehensive overview of the Model Method. However, its price of $32 (if I remember it correctly) is steep as compared to the usual guide/assessment books. But if you have a child in P3, you still have about 4 years to go, so 32/4 which is $8/year, this book is certainly a good buy.

For a great fan of Model Drawing,I wish this book has been published earlier.My learning curve will be much shortened.

I am sharing this book from the perspective of a father who has been struggling to keep pace with Primary Maths in his journey with his son. It’s from a father who has taken a much longer and tedious approach, and sincerely hopes that your learning journey will be a much pleasant one.

Wishing you every success.