Q&A - P4 Math

[BigDevil]

Laura02:

Jamesbond:

Pl explain me how to solve this. http://i49.tinypic.com/2vnj67k.jpg\">

Let me try ...

2 plants for every 4m and 5 lanterns for every 6m. So for every 12m (lowest common multiple of 4 & 6), there will be 2 X 3 plants and 5 X 2 lanterns. Guess & check :
Length........ 12m....24m....36m....48m....60m....72m
Plants..........6.........12......18.......24.......30......36
Lanterns.......10.......20......30.......40.......50.....60

Therefor if the corridor is 72m long, there will be 24 more lanterns th an plants.

Cheers!

There are only 2 x 2 plants, not 2 x 3.

At 12m, there are 10 lanterns and 4 plants.
So for every 12m, there are 6 lanterns more than plants.

To get 24 (6 x 4) lanterns more than plants, you need 4 times of 12m more.

12 x 4 = 48m

[AgonyMum]

Hello, please show me the correct "formula" ie the pattern of these 2 questions.Thanks!


1. Figure 1 - 1 cube
Figure 2 - 5 cubes
Figure 3 - 14 cubes

How many cubes are needed to build Figure 10?
(Use patterns, not calculations)

2. Deposit $1 in bank.
On second day, total amount will be $3
On third day, total amount will be $9
On fourth day, total amount will be $27 and so on.
How much money will there be at the end of 10 days?
(Use patterns, not calculations)

[MathIzzzFun]

AgonyMum:

Hello, please show me the correct \"formula\" ie the pattern of these 2 questions.Thanks!


1. Figure 1 - 1 cube
Figure 2 - 5 cubes
Figure 3 - 14 cubes

How many cubes are needed to build Figure 10?
(Use patterns, not calculations)

2. Deposit $1 in bank.
On second day, total amount will be $3
On third day, total amount will be $9
On fourth day, total amount will be $27 and so on.
How much money will there be at the end of 10 days?
(Use patterns, not calculations)

Hi

may I know the source of these questions ?

Q1 is a pattern of 3rd order (ie cubic - sum of squares, pattern 1 =1 , pattern 2 = 1x1 + 2x2, pattern 3 = 1x1+2x2+3x3, nth term = n(n+1)(2n+1)/6 ) and as far as I know, P6 students are only required to find pattern or nth term for pattern of 2nd order. For 3rd order pattern, the students are only required to evaluate the nth term based on observation and usually, the nth term is usually less than 10.
So, this question is certainly not a standard P4 question, more likely practice question for maths competition.


Q2. day 1 - 1, day 2 - 1x3 = 3^1, day 3 - 1x3x3 = 3^2, day 10 = 3^9.
again, I think this is beyond P4 maths.

cheers.

[AgonyMum]

Hi MathIzzzFun,

These are GEP questions.
Regarding Q. 2, does your symbol ^ refer to " to the power of" ?

TQ!

[MathIzzzFun]

AgonyMum:

Hi MathIzzzFun,

These are GEP questions.
Regarding Q. 2, does your symbol ^ refer to \" to the power of\" ?

TQ!

yes, 3^2 = 3²

cheers.

[Laura02]

BigDevil:

Laura02:

[quote=\"Jamesbond\"]Pl explain me how to solve this. http://i49.tinypic.com/2vnj67k.jpg\">

Let me try ...

2 plants for every 4m and 5 lanterns for every 6m. So for every 12m (lowest common multiple of 4 & 6), there will be 2 X 3 plants and 5 X 2 lanterns. Guess & check :
Length........ 12m....24m....36m....48m....60m....72m
Plants..........6.........12......18.......24.......30......36
Lanterns.......10.......20......30.......40.......50.....60

Therefor if the corridor is 72m long, there will be 24 more lanterns th an plants.

Cheers!

There are only 2 x 2 plants, not 2 x 3.

At 12m, there are 10 lanterns and 4 plants.
So for every 12m, there are 6 lanterns more than plants.

To get 24 (6 x 4) lanterns more than plants, you need 4 times of 12m more.

12 x 4 = 48m[/quote]Oops! Thanks for the correction. Didn't remember the question correctly coz was using phone to answer the ques.

R the any teachers out there? Will th kids be given marks for correct concept but obviously careless?

[Jamesbond]

http://i49.tinypic.com/mhf3a9.jpg\">


pl help me solve this......

[Jamesbond]

http://i46.tinypic.com/2573bds.jpg\">


The ans for ques (a) is 15 unit shapes...I donno to solve ques (b). Pl help me...............

[MathIzzzFun]

Jamesbond:

http://i46.tinypic.com/2573bds.jpg\">


The ans for ques (a) is 15 unit shapes...I donno to solve ques (b). Pl help me...............

Hi

pattern 1 --> 1 = 1x2 /2
pattern 2 --> 3 = 2x3 /2
pattern 3 --> 6 = 3x4 /2
pattern N = N x (N+1) /2 --> 1/2 x product of pattern number N and the next consecutive number
pattern 5 --> 5x6 /2 = 15

Total = 210
ie 1/2 x product of pattern number N and the next consecutive number = 210
or product of 2 consecutive numbers (N & N+1) = 420
.. use guess and check to find the number N --> the nearest square number = 400 = 20 x 20
20 x 21 = 420
N = 20
Pattern 20 has 210 shapes

cheers.

[Laura02]

MathIzzzFun:

AgonyMum:

Hello, please show me the correct \"formula\" ie the pattern of these 2 questions.Thanks!


1. Figure 1 - 1 cube
Figure 2 - 5 cubes
Figure 3 - 14 cubes

How many cubes are needed to build Figure 10?
(Use patterns, not calculations)

2. Deposit $1 in bank.
On second day, total amount will be $3
On third day, total amount will be $9
On fourth day, total amount will be $27 and so on.
How much money will there be at the end of 10 days?
(Use patterns, not calculations)

Hi

may I know the source of these questions ?

Q1 is a pattern of 3rd order (ie cubic - sum of squares, pattern 1 =1 , pattern 2 = 1x1 + 2x2, pattern 3 = 1x1+2x2+3x3, nth term = n(n+1)(2n+1)/6 ) and as far as I know, P6 students are only required to find pattern or nth term for pattern of 2nd order. For 3rd order pattern, the students are only required to evaluate the nth term based on observation and usually, the nth term is usually less than 10.
So, this question is certainly not a standard P4 question, more likely practice question for maths competition.


Q2. day 1 - 1, day 2 - 1x3 = 3^1, day 3 - 1x3x3 = 3^2, day 10 = 3^9.
again, I think this is beyond P4 maths.

cheers.

Hi!

Could the be more than one answer for Q1?

Say 1 (+4) = 5
5 (+4+5) = 14
14 (+4+5+6) = 29
29 (+4+5+6+7) = 51 ... Ans 283

I'm not a math teacher, so please correct me if I'm wrong.

Which is why maths is fun!