Q&A - PSLE Math

[StaryNight]

lee tong fong:

Thanks for your detail working solution. It is difficult to explain to kid the equal fraction concept


70% of remainder = 42% of salary .... equal fraction
70/100 of remainder = 42/100 of salary
remainder = 6/10 of salary

Is there any simplify way to do so . Thanks

Hi lee tong fong,
maybe you could do it using ratio
70/100 Remainder = 42/100 Salary
7/10 Remainder = 21/50 Salary
make the numerator (top number of fraction) the same
21/30 Remainder = 21/50 Salary

now make it into a ratio

Remainder: Salary
30 : 50
=3 : 5

then the rest should be ok

5u-3u=2u
2u--> 480
1u--> 480/2= 240
5u--> 240*5=1200
20% of 1200 = 20/100*1200=240

Hope this helps!

[Maths Hub]

lee tong fong:

Thanks for your detail working solution. It is difficult to explain to kid the equal fraction concept


70% of remainder = 42% of salary .... equal fraction
70/100 of remainder = 42/100 of salary
remainder = 6/10 of salary

Is there any simplify way to do so . Thanks

Referring to the method I showed earlier, we use 100 units for 100% of salary as some children find it hard to understand percentage equals to another percentage of different base.

However, if you use the method of equal numerator method as mentioned by MathIzzzFun and StaryNight, you can use model method to show your child the whole concept of why we make the numerator the same.

Hope it helps!

[MathIzzzFun]

lee tong fong:

Thanks for your detail working solution. It is difficult to explain to kid the equal fraction concept


70% of remainder = 42% of salary .... equal fraction
70/100 of remainder = 42/100 of salary
remainder = 6/10 of salary

Is there any simplify way to do so . Thanks

from 70/100 of remainder = 42/100 of salary,
remainder = 42/100 of salary ÷ 70/100 = 42/100 of salary x 100/70
remainder = 42/70 of salary = 6/10 of salary ...basically this is the same as equalizing the numerators to get the ratios, but I have shorten the process.

here's why you can equalize the numerators to arrive at the ratio of the two variables...

http://tinyurl.com/mathizzzfun-equalFractions

cheers.

[bestwishes]

lee tong fong:

Thanks for your detail working solution. It is difficult to explain to kid the equal fraction concept


70% of remainder = 42% of salary .... equal fraction
70/100 of remainder = 42/100 of salary
remainder = 6/10 of salary

Is there any simplify way to do so . Thanks

Maybe u shd get this book ... Will definitely help kids to master various qns involving fraction, ratio or percentage. Try to contact the publisher directly to get more discount and free delivery. (I did!)



http://www.popular.com.sg/jsp/product/product_detail.jsp?vca001=112&vpd001=99464

[lee tong fong]

Thank you MathlzzzFun, StaryNight, Math Hub and bestwishes for your generous contribution and it is much easier now for the child to understand equal percentage concept of making a certain percentage equals to another percentage of different base. The model and the detail equal numerator method is great help to the child the show them why we make the numerator the same in order to solve the problem. Thanks

[happyheart]

Hi,

Need help to solve these using model please.

Q) If Jeremy gives 15 stickers to Ramesh, he will have four times as many stickers as Ramesh. If Ramesh gives 5 stickers to Jeremy, the ratio of Jeremy’s stickers to Ramesh stickers would be 14:1. How many stickers does Jeremy have?

Q) Four children, Wilson, Felicia,Darren and Annabel sat for Math test and scored a total of 318 marks. Wilson and Darren scored the highest and the lowest respectively with a difference of 27 marks. The difference between Felicia’s and Darren’s score was 5 marks and the difference between Wilson’s and Annabel’s score was 13 marks. Find their individual scores.

Thank you!

[happyheart]

One more similar question please, to solve using model drawing.


Q3) Four children, Wilson, Felicia Daresn and Annabel sat for a Math test and scored a total of 318 marks. If we take any 3 of their scores, we will get an average of 75,78 and 81 respectively. Wilson and Darren scored the highest and lowest respectively. Find the total score of Wilson and Darren.

Thank you.

[MathIzzzFun]

happyheart:

One more similar question please, to solve using model drawing.


Q3) Four children, Wilson, Felicia Daresn and Annabel sat for a Math test and scored a total of 318 marks. If we take any 3 of their scores, we will get an average of 75,78 and 81 respectively. Wilson and Darren scored the highest and lowest respectively. Find the total score of Wilson and Darren.

Thank you.

the 4 scores are :
score #1 --> 318 - 3 x 75 = 93
score #2 --> 318 - 3 x 78 = 84
score #3 --> 318 - 3 x 81 = 75
score #4 --> 318 - 93 - 84 - 75 = 66
..from these, you should be able to determine the scores of Wilson & Darren.

cheers.

[MathIzzzFun]

happyheart:

Hi,

Need help to solve these using model please.

Q) Four children, Wilson, Felicia,Darren and Annabel sat for Math test and scored a total of 318 marks. Wilson and Darren scored the highest and the lowest respectively with a difference of 27 marks. The difference between Felicia's and Darren's score was 5 marks and the difference between Wilson's and Annabel's score was 13 marks. Find their individual scores.

Thank you!

You may want to draw the model ... I will represent Darren's block as 1 unit

Darren --> 1 unit
Wilson --> 1 unit + 27
Felicia --> 1 unit + 5
Annabel --> 1 unit + 14 (*= Wilson's score - 13)

So, 4 units (or 4 blocks in model) + 46 = 318
1 unit --> 68
...with this, the individual can then be worked out...

cheers.

[happyheart]

MathIzzzFun:

happyheart:

Hi,

Need help to solve these using model please.

Q) Four children, Wilson, Felicia,Darren and Annabel sat for Math test and scored a total of 318 marks. Wilson and Darren scored the highest and the lowest respectively with a difference of 27 marks. The difference between Felicia's and Darren's score was 5 marks and the difference between Wilson's and Annabel's score was 13 marks. Find their individual scores.

Thank you!

You may want to draw the model ... I will represent Darren's block as 1 unit

Darren --> 1 unit
Wilson --> 1 unit + 27
Felicia --> 1 unit + 5
Annabel --> 1 unit + 14 (*= Wilson's score - 13)

So, 4 units (or 4 blocks in model) + 46 = 318
1 unit --> 68
...with this, the individual can then be worked out...

cheers.

MathIzzzfun...you make both questions look so simple. Thank you!