Q&A - P5 Math

[tianzhu]

memouse:

Hi, I'm having mental block trying to solve this. Anyone can help to? Thank u so much.


Qn:
Weili used 2 strings of the same length to make 2 necklaces. For the 1st necklace, she used 2 big beads for evey 4 cm of string. For the 2nd necklace, she used 5 small beads for every 3cm of string. She used 84 more small beads than big beads.
a) Find the total number of big beads Weili used.
b) Find the total number of beads Weili used for the 2 necklaces.

Hi

A common multiple for 4cm and 3cm is 12cm.

For a set of 12cm, there are 6 big beads and 20 small beads.

Difference per set ------ 14

Number of set of 12cm ------- 84/14 ------ 6

Number of big beads ------- 6*6 ------ 36

Total number of beads -------- 6*26 ------ 156

Best wishes

[tianzhu]

memouse:

Hi, need help to find answer to this qn. Thank u.


Qn:
Mrs Wong had some cookies to give her pupils. If she gave each of them 3 cookies each, she would have 5 left over. If she gave each pupil 4 cookies, she would need 3 more cookies. How many pupils were there?

Hi

You may use “SL” or “Excess and Shortage “

In order to give her pupils one more cookie each, Mrs Wong needs 8 (5+3) cookies

Number of pupils ------ 8/1 ------ 8

Best wishes

[tianzhu]

cookieandmonster:

Hi, need help in this question. Thank you.


Qn:
The number of books on Shelf Y was 62 more than that on Shelf X. When 31 books were transferred from Shelf X to Shelf Y, the number of books on Shelf Y became 3 times as many as the number of books on Shelf X. How many books were there on Shelf X at first?

Hi

A neat way is to use MD.

Hope this helps.

Best wishes

http://farm9.staticflickr.com/8505/8582142992_0972a69db3_z.jpg\">

[memouse]

tianzhu:

memouse:

Hi, I'm having mental block trying to solve this. Anyone can help to? Thank u so much.


Qn:
Weili used 2 strings of the same length to make 2 necklaces. For the 1st necklace, she used 2 big beads for evey 4 cm of string. For the 2nd necklace, she used 5 small beads for every 3cm of string. She used 84 more small beads than big beads.
a) Find the total number of big beads Weili used.
b) Find the total number of beads Weili used for the 2 necklaces.

Hi

A common multiple for 4cm and 3cm is 12cm.

For a set of 12cm, there are 6 big beads and 20 small beads.

Difference per set ------ 14

Number of set of 12cm ------- 84/14 ------ 6

Number of big beads ------- 6*6 ------ 36

Total number of beads -------- 6*26 ------ 156

Best wishes

Thanks alot for the solution. Appreciate it.

[memouse]

tianzhu:

memouse:

Hi, need help to find answer to this qn. Thank u.


Qn:
Mrs Wong had some cookies to give her pupils. If she gave each of them 3 cookies each, she would have 5 left over. If she gave each pupil 4 cookies, she would need 3 more cookies. How many pupils were there?

were there?
Hi

You may use “SL” or “Excess and Shortage “

In order to give her pupils one more cookie each, Mrs Wong needs 8 (5+3) cookies

Number of pupils ------ 8/1 ------ 8

Best wishes

Thank u very muchie. :boogie:

My boy used guess and check to solve this:

- 1st;
6x3x5 =23
7x3x5 =26
8x3x5 =29

- 2nd;
6x4x3 =21
7x4x3 =25
8x4x3 =29

Check that answer for 1st and 2nd must be the same, hence the answer is 8. Is this method feasible and ok to use. Thank u

[tianzhu]

memouse:

Check that answer for 1st and 2nd must be the same, hence the answer is 8. Is this method feasible and ok to use. Thank u

Hi

Yes, you may use GC, but it is less efficient at upper primary level as the numbers are bigger.

Let your boy try to use GC for this question.

Mr Chia gives some erasers to his students. If he gives 7 erasers to each student, he will have 53 erasers left. If he gives 9 erasers to each student, he will have 5 erasers left.
(a) How many students does he have?
(b) Find the number of erasers he has at first.

Usually under examination environment, students are hard pressed to finish the questions within tight schedule and a more efficient method would be more advisable.

Best wishes

[memouse]

tianzhu:

memouse:

Check that answer for 1st and 2nd must be the same, hence the answer is 8. Is this method feasible and ok to use. Thank u

Hi

Yes, you may use GC, but it is less efficient at upper primary level as the numbers are bigger.

Let your boy try to use GC for this question.

Mr Chia gives some erasers to his students. If he gives 7 erasers to each student, he will have 53 erasers left. If he gives 9 erasers to each student, he will have 5 erasers left.
(a) How many students does he have?
(b) Find the number of erasers he has at first.

Usually under examination environment, students are hard pressed to finish the questions within tight schedule and a more efficient method would be more advisable.

Best wishes

Tianzhu, thank u. Will ask my boy to try the qn wh u gave with G&C.

[carol73]

Joanne paid a total of $52 for 2 similar blows and 2 similar plates

five bowls cost as much as three plates
how much money would joanne save if she bought two bowls and 2 plates

[tianzhu]

carol73:

Joanne paid a total of $52 for 2 similar blows and 2 similar platesfive bowls cost as much as three plates

how much money would joanne save if she bought two bowls and 2 plates

Hi

Please check with your source.

A similar question was discussed in the P4 thread.

Hope this helps.

Best wishes

http://farm9.staticflickr.com/8086/8551140688_ab09f44b7a_z.jpg\">

[shann2]

Need some help. TIA!


1. 5/8 of Ann’s stamps is equal to 2/5 of Tony’s stamps. If Tony gives 18 stamps to Ann, they will then have the same number of stamps. How many stamps do they have altogether?

2. Mary spent $270 on a necklace. She spent 1/7 of her money on a dress. She then had 3/8 of her money left. How much money did she have at first?

3. Yesterday, Ron had 72 more stamps than Lisa. Today, Ron gave Lisa 2/5 of his stamps. As a result, he has 1/2 as many stamps as Lisa now. How many stamps did Ron have yesterday?