SG
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Secondary 3
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Number and Algebra

Pls assist dunno how to solve.

Replies
1

Meng Khim Goh

Digits of 2007 adds up to 9. 1000 chain of 2007 will have total sum of digits 9000.
n is 4, and its number 2007 has 9 as its sum of digits.
m makes a number that has sum of digits of 9000-7999-9=992
992รท9=110r2
So m has 110 "2007"s and another 2.
The largest number that m can form will be 110 chain of "2007"s followed by 200.
110x4+3=443
Thus the largest value m can be is 443.
443-4=439

2 years ago

Cynthia Tay

Asked 5 years ago

SG
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Thanks for adding! Finding here helpful especially nowadays primary maths are so different from my time... I m learning here too

I worked to a point where 5 u is 18 and cannot get a whole number sticker either...

2 years ago

Jessie Hong Yin Wei

Possibly mistake in qn?

2 years ago

Pieter Cronje

2 years ago

Yueh Mei Liu

Yep. I think the difference in stickers bet Megan and Kayla should be multiples of 5.

2 years ago

Jessie Hong Yin Wei

Yueh Mei Pieter CronjeThank you

2 years ago

Mayuree Thongpan

Asked 5 years ago

SG
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Primary 5
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Number and Algebra

Is this the correct way to explain P.5 students?Does anyone have suggestion or another better way?

Replies
9

Kwek YenPing

Actually this is not within syllabus. Can forget abt it.

2 years ago

Mayuree Thongpan

You mean, the syllabus in P.5 not include the question like this?
It's my kid's homework.

2 years ago

Kwek YenPing

Yes. They do not compare percentage with percentage. Only fractions. School over teaching.

2 years ago

Yueh Mei Liu

Yep. Kwek YenPing is correct.

2 years ago

Tan Weiqiang

many schools are doing this...saw on Kiasuparents forum today...some ridiculous questions posted by parents...An example being A + B = 20, A + A + A = B + B. What is A and B? at P1....*shake head*

2 years ago

Mayuree Thongpan

In P3 question like::
there are 12 chickens and pigs. There are 30 legs in total. How many chickens and how many pigs are there?
Normally, in level P3 which method do you teach in Singapore, between "guess and check" and find the difference -->
12*2=24
30-24=6
6/2=3
12-3=9
If teacher won't allow using Guess and Check in P3, how do we teach about difference without picture, just only number sentences?

2 years ago

Yueh Mei Liu

Suppose all the animals are chickens. Sup there are 12x2=24 legs.
Qn says that there are 30 legs, so there are 30-24=6 legs that need to be used.
For each chicken, if we put in another 2 legs, that'll make the chicken into a pig.
With 6 legs, we can convert 3 chickens into pigs.
Hence there are 3 pigs and 9 chickens.

2 years ago

Yueh Mei Liu

Above is the explanation and understanding part.
Student should be having the reasoning in their head as they are working out the steps

2 years ago

Mayuree Thongpan

This technique we should start at level P3 or P4?
Mostly, teacher would teach which approach in P3?
Guess n check or the explanation of extra legs.
I try to teach my kid by teaching.. Like this..
12 chickens have 24 legs. There are 6 extra legs which can make a magic to transform chickens to become pigs, 1 chicken needs 2 legs to transform to be 1 pig.
You have 6 extra legs so you can make a magic only 3 chickens to be 3 pigs.
:p

Honestly when I look at this problem, I do not know if I should assume Nuriz buying the rest of the pens and erasers because it was not explicit in the problem statement, the way Thit Mon Mon Win did. Is there any clue or hint in the question that suggest that?