PSLE - New Format for Maths

[kohjl]

pinky88:

Tks Vanilla cake for the qn & soln. u're really fantastic in Maths. Can solve all the prob. sums. The Uncle observer's blog was interesting. Tks again.

pinky88
Vanilla Cake is a Year 2 student in NUS High Sch if I remember rightly. I agree with you that VCake is fantastic in Maths, and to top it all, is very helpful and is an asset to this forum! As a parent, I value VCake's contributions and I am sure NUSHS is very proud of him/her.

Vanilla Cake - Thanks for your many good and helpful contributions!

[caroline3sg]

yes, vanilla cake is great & very helpful.


Glad to have you here in this forum.

[father_of_3]

fyi, that geometry question is 5 marks.

[Bl8de]

happypoppy:

Hi Bl8de,


It was given in the question that AD = AC = AB.

Since AC is perpendicular to BD, AC = KL (which in turn) = LM (as this is a square) = BD (question states that ML and BD are parallel).

Once it has been established that BD = AD = AB, triangle ADB is essentially an equilateral triangle. Therefore angle DAB = 60 degrees and angle DAC = 60 degrees / 2 = 30 degrees.

In view that triangle DAC is an isosceles triangle, angle b = 75 degrees and the required angle DCB = 75 degrees x 2 = 150 degrees.


NB: BTW, it was DH that solve the question for me. I was mulling over it for ages when he came over and solve it in 5 mins flat! I guess geometry is one of those questions that either you have the flair for it or you dont.

Did the question state that i is a square? Because I still dont see why KL = LM. There is no specific evidence for that.

[karmeleon]

Bl8de:

happypoppy:

Hi Bl8de,


It was given in the question that AD = AC = AB.

Since AC is perpendicular to BD, AC = KL (which in turn) = LM (as this is a square) = BD (question states that ML and BD are parallel).

Once it has been established that BD = AD = AB, triangle ADB is essentially an equilateral triangle. Therefore angle DAB = 60 degrees and angle DAC = 60 degrees / 2 = 30 degrees.

In view that triangle DAC is an isosceles triangle, angle b = 75 degrees and the required angle DCB = 75 degrees x 2 = 150 degrees.
.

Did the question state that i is a square? Because I still dont see why KL = LM. There is no specific evidence for that.

Yes, it says it's a SQUARE.

I also can't see how \" AD = AC = AB \"

[harini]

turquoise:

Article about PSLE Math paper in Today newspaper:


http://www.channelnewsasia.com/stories/singaporelocalnews/view/1010464/1/.html

Thanks!!! Read it, hope MOE is hearing .

[harini]

Anybody knows the question and answer for the circle area and perimeter question. It carried 5 marks …

[StudentABC]

:? Huh? But I remember that most questions carried 4 marks except the one on raj and devi's salary???only that question carried 5 marks...


Geometry- 4marks
Speed - 3marks
chocs and sweets- 4marks
raj and devi- 5marks
balloon- 4 marks

(P.S: I took the paper too and I did not know how to solve 4 questions so I paid extra attention to the marks awarded. Luckily I solved 3 but left the last one untouched(the one on speed).But i got the geometry wrong. :stupid: )

I think I die le. I went home and cried that day. In fact many ppl could not complete. i left the last step of the speed question untouched....It seems only 3 ppl from my school found the paper easy. But then they are the best at tackling competition maths questions in our school...1 of them said he got all questions correct so far.by the way, is the last question really 68??? So sad... :stupid: :!: :!:

[mathsparks]

Hey studentabc,

don’t let the maths paper affect you. Stop checking answers already! Stay away from this forum…go focus on yr science. Shoo!!

[Guan Hui]

Hello this is what I get from the channelnewsasia forum. I am a tuition teacher who has students taking PSLE so I am quite concern too. Below are the questions and the suggested answers I provide.


PSLE Maths - some of the questions
Mei and Lin were in a bicycle race. Mei was travelling at a constant speed of 20km/hr and they both did not change their speed. When Lin completed half the race, Mei was 3.5km ahead. Mei completed the race at 10.45am. What time did Lin complete the race? Ans: 11.06am

Suggested Answer:
3.5 x 2 = 7km(how much ahead is mei if she keep cycling when Lin finish the race)

speed= 20km/h
7km= 7/20 X 1
=0.35 hr
=21 mins (time needed to be 7km ahead for mei)
Time when Lin complete the race = 10.45am+ 21mins
= 11.06am




Sally baked some cookies to sell. 3/4 of them were chocolate cookies and the remaining were almond cookies. After she sold 5/6 of chocolate cookies and 210 almond cookies, she had 1/5 of the cookies left. How many cookies did she sell? Ans: 960

Suggested Answer:
5/6 of chocolate cookie = 5/6 x 3/4
= 5/8 of total cookie (SOLD)
Faction of cookie sold = 1- 1/5
=4/5
Fraction of Almond cookie Sold = 4/5 - 5/8
= 7/40(SOLD == 210 almonds)
4/5= 32/40

7units =210 almonds
32 units = 32/7 x 210
= 960 cookies

Jim bought some chocolates and gave half of it to Ken. Ken bought some sweets and gave half of it to Jim. Jim ate 12 sweets and Ken ate 18 chocolates. The ratio of Jim’s sweets to chocolates became 1 : 7 and the ratio of Ken’s sweets to chocolates became 1:4. How many sweets did Ken buy?. Ans: 68 sweets

Suggested answer:

Jim Ken
sweet : Choco Sweet : Choco
1Junit : 7Junits 1Kunit: 4Kunits
1Junit+12 : 7Junits 1Kunit: 4Kunits +18 (before eating the sweets and the chocolates)

Since at the beginning they have the same number of sweets and chocolates.
1Junit + 12 = 1Kunit
4Junits +48 = 4Kunits
4Junits + 66 = 4Kunits +18 = 7Junits
3Junits= 66
1Junit= 22
Number of sweets Jim recieved at the beginning : 22 +12 =34 sweets
Number of sweets Ken buy : 34 +34 =68 sweets
(Regret cant show in model)

Curry puff shop sells puffs at $0.80 each. Offer:Buy 3 get 4th half price. If customer has $50, how many puffs can he buy if he buys as many as he can. Ans: 71 puff

Suggested Answers:
3 puffs : $0.80 x 3 =$2.40
4th puff: $0.80 / 2 =$0.40
1 set of 4 puffs cost: $2.40+$0.40=$2.80
Number of sets the customer can buy with $50: 50/2.8=17 sets and $2.40 left
Number of puffs $2.40 can buy: $2.40/$0.80 = 3puffs
Number of puffs in 17 sets: 17x 4 = 68 puffs
Total number of puffs: 68 +3=71 puffs

String of 2 big balloons is 90cm
String of 5 small balloons is is 1.2m
If both strings are of the same length, there would be 105 more small balloons than the big balloons. How many balloons are there altogether? Ans: 345

Suggested Answers:
String of 1 big balloon: 90cm/2 = 45cm
String of 1 small balloon: 120cm/5 = 24 cm
difference in the length of string: 45-24=21 cm
how much longer if they have the same number of big balloons and small balloons: 105(small balloons more) x 24= 2520 cm
The number of big balloons that will cause this difference: 2520/ 21 = 120
Number of big balloons: 120 balloons
Number of small balloons 120+105=225 balloons
Total: 120+225= 345 balloons

This is my 10cent worth of solution hope it helps to further confirm your children answers. Anymore enquires about maths you can call me at 94503822=) I will gladly assist you.
Good luck to all those children taking science and higher chinese next week=)