Q&A - P5 Math

[PiggyLalala]

YumYum:

Hi, can anyone pls help with this qn:


David has 10% fewer cookies Ian but 40% more cookies than Rauf. If they have a total of 890 cookies, how many cookies does Ian have? Thks

Rauf: 100%
David: 140%
Ian: 100/90 x 140% = 1400/9%

Total = 100 + 140 + 1400/9 % --- 890 cookies
3560/9 % ---- 890 cookies
1400/9 % ----890 x 1400/3560 =350 cookies

[YumYum]

Hi PiggyLalala, many thanks!

[happyheart]

Hi,

Can someone explain & illustrate this questions with model?

Q) Mr. Chua has a class of less than 40 pupils. He gave all the pupils in his class some jellybeans. If he gave 5 jellybeans to each pupil, he would have 2 jellybeans left. If he gave 4 jellybeans to each pupil, he would have 38 jellybeans left.

a) How many pupils were there in his class?
?) How many jellybeans did Mr Chua have?

Thanks.

[tianzhu]

happyheart:

Hi,

Can someone explain & illustrate this questions with model?

Q) Mr. Chua has a class of less than 40 pupils. He gave all the pupils in his class some jellybeans. If he gave 5 jellybeans to each pupil, he would have 2 jellybeans left. If he gave 4 jellybeans to each pupil, he would have 38 jellybeans left.

a) How many pupils were there in his class?
?) How many jellybeans did Mr Chua have?

Thanks.

Hi

This is a typical question under “Gap and Difference” or “Excess and Shortage”. Different books labelled them differently.

There are a few approaches, while a visual representation may help students to see better in the beginning, it’s usually not necessary once they become more familiar with the logic behind the solution.

Try to see it from this angle,to give each pupil one less jellybean (5-4), Mr Chua would have 36 (38-2) more jellybeans left.

Number of pupils ------- 36/1 ------- 36

Number of jellybeans -------- 36*5 + 2 ------- 182

Alternatively (36*4) + 38 ------- 182

Other approaches include “Multiple method” which involves listing of multiples. Another possible way is to work with units.

Here’s a solution for a similar type of question. Hope you’ll find it useful.

Best wishes

http://farm7.staticflickr.com/6176/6193593312_fe5ffb9348_z.jpg\">

[happyheart]

tianzhu:

happyheart:

Hi,

Can someone explain & illustrate this questions with model?

Q) Mr. Chua has a class of less than 40 pupils. He gave all the pupils in his class some jellybeans. If he gave 5 jellybeans to each pupil, he would have 2 jellybeans left. If he gave 4 jellybeans to each pupil, he would have 38 jellybeans left.

a) How many pupils were there in his class?
?) How many jellybeans did Mr Chua have?

Thanks.

Hi

This is a typical question under “Gap and Difference” or “Excess and Shortage”. Different books labelled them differently.

There are a few approaches, while a visual representation may help students to see better in the beginning, it’s usually not necessary once they become more familiar with the logic behind the solution.

Try to see it from this angle,to give each pupil one less jellybean (5-4), Mr Chua would have 36 (38-2) more jellybeans left.

Number of pupils ------- 36/1 ------- 36

Number of jellybeans -------- 36*5 + 2 ------- 182

Alternatively (36*4) + 38 ------- 182

Other approaches include “Multiple method” which involves listing of multiples. Another possible way is to work with units.

Here’s a solution for a similar type of question. Hope you’ll find it useful.

Best wishes

http://farm7.staticflickr.com/6176/6193593312_fe5ffb9348_z.jpg\">

This is great! Tianzhu. Thank you so much:)

[YumYum]

Hi, I need help with this question:


Mrs Yeo had 60% more books than mrs lim. Miss tang had 25% fewer books than Mrs Yeo. Mrs Yeo and Mrs Lim gave Miss Tang a number of books in the ratio 3:1. As a result, miss tang had 1.5 times as many books as before. Given that mrs yeo had 240 books more than mrs Lim in the end, how many books did Mrs Yeo give to Miss Tang? Thks

[MathIzzzFun]

YumYum:

Hi, I need help with this question:


Mrs Yeo had 60% more books than mrs lim. Miss tang had 25% fewer books than Mrs Yeo. Mrs Yeo and Mrs Lim gave Miss Tang a number of books in the ratio 3:1. As a result, miss tang had 1.5 times as many books as before. Given that mrs yeo had 240 books more than mrs Lim in the end, how many books did Mrs Yeo give to Miss Tang? Thks

Hi

AT first,
Yeo : Lim --> 160 : 100 = 8 : 5
Yeo : Tang --> 4 : 3 = 8 : 6
So, Yeo : Lim : Tang --> 8u : 5u : 6u

Books given by Yeo and Lim = 50% x 6u = 3u
Books given by Yeo = 3/4 x 3u = 2.25u
Books given by Lim = 3u - 2.25u = 0.75u
Books left, Yeo : Lim = 8u-2.25u : 5u-0.75u = 5.75u : 4.25u
Yeo had 240 books more than Lim --> 1.5u = 240
1u --> 160
Books given by Yeo = 2.25 x 160 = 360

cheers.

[yamhh]

Need help for the below question:-

The average height of a group of children was 139.4cm. When Mr Tan measured and recorded the height of these children, he wrongly recorded one child's height as 192cm when it should have been 129cm. As a result, Mr Tan calculated the average height as 142.4cm. How many children were there in the group?

Many thanks in advance...

Yam

[yamhh]

Need help for the below question:-

The average height of a group of children was 139.4cm. When Mr Tan measured and recorded the height of these children, he wrongly recorded one child’s height as 192cm when it should have been 129cm. As a result, Mr Tan calculated the average height as 142.4cm. How many children were there in the group?

Many thanks in advance…

Yam

[lion_city]

Ans: 21


192-129=63
142.4-139.4=3
63/3=21