Thread: hee hee need help in Pri 4 Maths (again)

1. Re: hee hee need help in Pri 4 Maths (again)

Originally Posted by ziploc
Putting it into equations:

G = (H + D) % 10, X = INT((H + D) / 10)
K = (A + E + X) % 10, Y = INT((A + E + X) / 10)
F = (K + J + Y) % 10, Z = INT((K + J + Y) / 10)
H = K + K + Z

As you can see above, I don't think you can't solve it via algebra as there are simply not enough info - nothing that defines D, A, E, J. It can only be done by brute force substitution.
it's not that you can't.

can't suggests a lack of ability to do so.

you can, but brute force does it much more efficiently.. ironically.

2. Re: hee hee need help in Pri 4 Maths (again)

Originally Posted by brapodam
No they're putting too much stress on pri sch students. What kind of rubbish is this? We learn simple algebra like 3x + 4y = 15, 2x + y = 10, calculate x and y this kind of qn in sec 2, what kind of question is this?

Next thing you know they'll start teaching complex numbers and hypothesis testing in kindergarten...seriously
well, no one ever said that examinations should be just about regurgitating methods taught to you in class, with just a few modifications here and there to make them "more challenging" (when they are not).

if that is the case, if academic ability is about brute force memorisation, then it can encompass brute force trial and error methods too, right?

i fail to see how setting a goal for primary school students where they could get full marks in mathematics examinations by studying enough will aid them in the long run. it's high time that kids get a taste of real life earlier on, so that the singaporean education system doesn't just produce a bunch of kids waltzing into secondary school, falling flat on their face when they can't get 100 marks for maths, and then start crying in class.

3. Re: hee hee need help in Pri 4 Maths (again)

Wahlao...I totally stone. Is this math or is this a letter to aunt angie?

I love A, but A love C while C hate K but C loves K. LOL

4. Re: hee hee need help in Pri 4 Maths (again)

Originally Posted by ziploc
Putting it into equations:

G = (H + D) % 10, X = INT((H + D) / 10)
K = (A + E + X) % 10, Y = INT((A + E + X) / 10)
F = (K + J + Y) % 10, Z = INT((K + J + Y) / 10)
H = K + K + Z

As you can see above, I don't think you can't solve it via algebra as there are simply not enough info - nothing that defines D, A, E, J. It can only be done by brute force substitution.
btw, i realised ur using programming logic
cause suddenly i realise the mod and int looks familiar to wad i did for my noi training

5. Re: hee hee need help in Pri 4 Maths (again)

Originally Posted by allenleonhart
LOL wont lar. brute force is just test numbers. pluck a few and try ur luck. not much to pluck in actually. K is the first one wanna identify, then guess H, (K+K) or (K+K+1)

which leaves u with 7 more numbers all DIFFERENT to guess with.

thats why i can do in 5 mins
hey don't forget, you're a jc1 student, and one who does decently in math. This qn is given to a pri 4 student...can they really solve it? maybe those prc scholars can, but what about locals?

6. Re: hee hee need help in Pri 4 Maths (again)

Originally Posted by brapodam
hey don't forget, you're a jc1 student, and one who does decently in math. This qn is given to a pri 4 student...can they really solve it? maybe those prc scholars can, but what about locals?
no lar. my jc 1 didnt teach me this

this one was familiar cause i encountered when i was p4-6 that time

u can imagine. i used to be a good boy and do 10 pages per assessment book per topic per day one

encounter this always use logic. what are the stuff i can link and limit first?

then brute force

7. Re: hee hee need help in Pri 4 Maths (again)

Originally Posted by brapodam
hey don't forget, you're a jc1 student, and one who does decently in math. This qn is given to a pri 4 student...can they really solve it? maybe those prc scholars can, but what about locals?
are you telling me that you need a few more years of education to dial in random numbers and do trial and error?

essentially, the skills needed here are:

1) carefulness
2) determination to get the answer

i believe 1 and 2 are part and parcel of examinations, 3 is taught by primary 4. i hope.

8. Re: hee hee need help in Pri 4 Maths (again)

1172
1643
2815

So as you can see, the answer is not exact, and there are many permutations. The question looks like something that was conjured up by a teacher too creative. And it looks more like IQ test than math.

9. Re: hee hee need help in Pri 4 Maths (again)

Originally Posted by night86mare
are you telling me that you need a few more years of education to dial in random numbers and do trial and error?

essentially, the skills needed here are:

1) carefulness
2) determination to get the answer

i believe 1 and 2 are part and parcel of examinations, 3 is taught by primary 4. i hope.
Yes but I dont think math should be about planting in random numbers and see if they fit. That should perhaps be part of a life skills workshop to develop people's perseverance and patience to solve the problem by testing a random range of numbers in the equation.

Sure, some logic is involved, but nothing much more than that. I thought they were already trying to discourage the "trial and error" method since the start of our education, why else would they teach us ways to work out "number pattern" style questions?

10. Re: hee hee need help in Pri 4 Maths (again)

Originally Posted by ziploc

1172
1643
2815

So as you can see, the answer is not exact, and there are many permutations. The question looks like something that was conjured up by a teacher too creative.
i am wondering if you can get K = 2.

i tried for a while, and i couldn't really get anything like that out.

11. Re: hee hee need help in Pri 4 Maths (again)

Originally Posted by brapodam
Yes but I dont think math should be about planting in random numbers and see if they fit. That should perhaps be part of a life skills workshop to develop people's perseverance and patience to solve the problem by testing a random range of numbers in the equation.

Sure, some logic is involved, but nothing much more than that. I thought they were already trying to discourage the "trial and error" method since the start of our education, why else would they teach us ways to work out "number pattern" style questions?

i think as long as the entire examination doesn't centre around 50 questions of that sort, it should be fine.

such questions can be a way to differentiate better students from the poorer ones - or perhaps how exam-smart you are. obviously, if i were a pri 4 student and i got this for my final examinations, i would realise quickly that this would be a waste of my time relative to the other "safer" questions, and leave it for last. then if i check my answers and i still have time, then can play with numbers for fun.

12. Re: hee hee need help in Pri 4 Maths (again)

Originally Posted by brapodam
Yes but I dont think math should be about planting in random numbers and see if they fit. That should perhaps be part of a life skills workshop to develop people's perseverance and patience to solve the problem by testing a random range of numbers in the equation.

Sure, some logic is involved, but nothing much more than that. I thought they were already trying to discourage the "trial and error" method since the start of our education, why else would they teach us ways to work out "number pattern" style questions?
Yes agree. This is not math but logic.

13. Re: hee hee need help in Pri 4 Maths (again)

Originally Posted by ziploc
Yes agree. This is not math but logic.
ziploc, try for a permutation for k is not equal to 1.

so far the ones we did, K=1 only

qn wants another value of K

if not K=1 means something else. got hidden logic that limits k=1

anyway to do it via Cprog? input value of K and guess value.

i think possible

14. Re: hee hee need help in Pri 4 Maths (again)

Originally Posted by night86mare
i am wondering if you can get K = 2.

i tried for a while, and i couldn't really get anything like that out.
Yes you can, like this:

2295
2731
5026

15. Re: hee hee need help in Pri 4 Maths (again)

Originally Posted by night86mare

i think as long as the entire examination doesn't centre around 50 questions of that sort, it should be fine.

such questions can be a way to differentiate better students from the poorer ones - or perhaps how exam-smart you are. obviously, if i were a pri 4 student and i got this for my final examinations, i would realise quickly that this would be a waste of my time relative to the other "safer" questions, and leave it for last. then if i check my answers and i still have time, then can play with numbers for fun.
at that age, i would have probably wasted the whole time trying to figure out how to do that, and will only give up after i realise the exam is about to end lol
Originally Posted by allenleonhart
ziploc, try for a permutation for k is not equal to 1.

so far the ones we did, K=1 only

qn wants another value of K

if not K=1 means something else. got hidden logic that limits k=1
later they change the qn to "find all the possible combinations of values of A, D, E, F, G, H, and K".

Right, go for it, math geek!

16. Re: hee hee need help in Pri 4 Maths (again)

Originally Posted by ziploc
Yes you can, like this:

2295
2731
5026
yes, seems correct.

whoever thought this question up needs to be shot.

if must give tedious question, at least make sure that you only have one answer, tsk.

17. Re: hee hee need help in Pri 4 Maths (again)

Originally Posted by allenleonhart
btw, i realised ur using programming logic
cause suddenly i realise the mod and int looks familiar to wad i did for my noi training
It is actually quotient and remainder, but since there is no symbol for quotient, I use programming representation. Here is another way of putting it (in words):

G = remainder((H + D) / 10), X = quotient((H + D) / 10)
K = remainder((A + E + X) / 10), Y = quotient((A + E + X) / 10)
F = remainder((K + J + Y) / 10), Z = quotient((K + J + Y) / 10)
H = K + K + Z

18. Re: hee hee need help in Pri 4 Maths (again)

Originally Posted by night86mare
yes, seems correct.

whoever thought this question up needs to be shot.

if must give tedious question, at least make sure that you only have one answer, tsk.
Well, nowadays they also want to teach creativity to students and not only confine to rules. This question does look like they are teaching trial-and-error.

19. Re: hee hee need help in Pri 4 Maths (again)

LOL WHERE GOT PRIMARY 4!! If really then i really fail......

Pass PSLE last year, also no such question....

20. Re: hee hee need help in Pri 4 Maths (again)

using logic K + K = H, H <=9 thus K can only be 1-4

so if K = 1, then H = 2 11A2 + 2JED = 2F1G
since 1 and 2 is taken, the rest of the letters = 3,4,5,6,7,8,9,0
using the additional of the second digit 'A' and 'E' A+E = 1 or 11 there for A,E = 5,6/4,7,3/8 (combination to form 11)
if we choose A, E as 5, 6 then the 1st digit 2 + D must be less than 10 else the 2nd digit is not true, thus if we sub D as 7 then 2 + 7 = G = 9
now left with 4,3,8,0
3rd digit K + J = F, since 2nd digit A+E we set as 11 therefore the 3rd digit will have a carry over, become 1+1+J = F === 2+J = F (F = 3/4/8/0) F cannot = 3 cause J is not 1, F cannot = 4 cause J is not 2 (K = 1 and H = 2) leaving 8 and 0 but 2 + J = F cannot have a carry over thus F cannot be 8 as A, E is 5, 6 and 0 is out

there for K = 1 is not possible, continue with K = 2 and H = 4, bah bah bah

when u get to K = 3 33A6 + 6JED = 6F3G
Numbers left = 1,2,4,5,6,7,8,9,0

same method start with A, E A + E = 13 (combination for A, E = 4,9/5,8/6,7)
set A, E as 4, 9 then your 3rd digit must be 1+3+J = F (F must be <9 so that there is no carry over) let J = 1 your 3d digit 1+3+1 = F (F=5)
so far numbers left are ( 2,7,8,0 )
last set of digits 6 + D = G (G < 10) thus 6 + D(D=2) = G(G=8)
numbers left ( 7,0 )

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