O-Level Elementary Math

PSLE marks the graduation of Primary school students and their entry into Secondary schools as teenagers. Discuss all issues about Secondary schooling here.
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Cookie123
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Re: O-Level Elementary Math

Post by Cookie123 » Thu Feb 14, 2019 11:39 pm

Which level is this?

Pand
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Re: O-Level Elementary Math

Post by Pand » Wed Mar 27, 2019 5:30 pm

S-H wrote:
Mon Oct 15, 2018 3:09 pm
Hi can somebody help me with this qtn, thank you!
The volume of a block is 0.03 cubic metres, correct to the nearest 0.01 cubic metres. Find the greatest possible height of the block in metres.
The question is incomplete.. you did not mention if shape of the block.. the only way to solve it is if it is a cube. Else.. the greatest possible height will be infinity...

This question is testing your understanding of upper bound.. it came out only once in the O level..(which killed many students).. other than that.. it has not come out yet..

How to approach..
Volume is 0.03.... ( correct to 0.01).. to find greatest possible height.. you need to know greatest possible volume... in this case the greatest possible volume is 0.03499999999999999999,,,, the upper bound is 0.035.
Take cube root.. and you will get greatest height possible if it is a cube.


If you do not understand why 0.0349999999999..... is 0,035... you need to understand why 0.9 recurring is equal to 1. Google or PM me..

have fun.

The Math Note
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Re: O-Level Elementary Math

Post by The Math Note » Thu Mar 28, 2019 11:05 am

0.034 rounded off to the nearest 0.01 is 0.03
0.025 rounded off to the nearest 0.01 is also 0.03

So anything between 0.025 and 0.034 rounded off to the nearest 0.01 is 0.03.

Hope that helps. 📏😊

Pand
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Re: O-Level Elementary Math

Post by Pand » Thu Mar 28, 2019 5:04 pm

The Math Note wrote:
Thu Mar 28, 2019 11:05 am
0.034 rounded off to the nearest 0.01 is 0.03
0.025 rounded off to the nearest 0.01 is also 0.03

So anything between 0.025 and 0.034 rounded off to the nearest 0.01 is 0.03.

Hope that helps. 📏😊
Sorry, unfortunately, your answer is wrong. I am a math teacher and am aware of the confusion this question causes to people not familiar with bounds.

The cambridge solution to a similar question in the o level is same as mine. Unfortunately, only teachers have access to the report.

jo sarah
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Re: O-Level Elementary Math

Post by jo sarah » Sat Mar 30, 2019 2:54 pm

Usually, if the question says a dimension is rounded to 0.01, the upper and lower bounds are found by taking that given dimension +/- 0.01/2 = 0.005.

So, in this case, they are 0.03 + 0.005 = 0.035 and 0.03 - 0.005 = 0.025

Hope this helps. :smile:


Pand
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Re: O-Level Elementary Math

Post by Pand » Sat Mar 30, 2019 5:18 pm

Sarah, you are right... but the reason why you take is because of
0.034999999999999 recurring is 0.035
This is the concept that o level is testing...
If not students will not understand because 0.035 rounded off to 0.01 is 0.04 ....

Candy08
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Re: O-Level Elementary Math

Post by Candy08 » Fri Apr 12, 2019 5:04 pm

Hi,
I need E math tutor for my DD. Anyone can recommend? We are staying in the West. Prefer do home tuition. My DD is now Sec 4 and struggling. TIA

Candy08
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Re: O-Level Elementary Math

Post by Candy08 » Fri Apr 12, 2019 5:04 pm

Hi,
I need E math tutor for my DD. Anyone can recommend? We are staying in the West. Prefer do home tuition. My DD is now Sec 4 and struggling. TIA

hanhui
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Re: O-Level Elementary Math

Post by hanhui » Sat Apr 13, 2019 11:51 am

Hi Candy08, I've private message you on my son's tutor. Graduated O level last yr with the tutor's help:) Not sure if he travels to West but you can text him to ask .
If you didn't receive my PM, you can email me for his contacts : lillianteoh74@gmail.com

Cheers!

Candy08
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Re: O-Level Elementary Math

Post by Candy08 » Thu May 09, 2019 12:39 pm

Thanks a lot!

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