Q&A - P3 Math

[tianzhu]

ginangly:

Hi all,


I need help with this qn.

Royston is 34 years younger than his father. 6 years ago, his father is 3 times as old as him. How old is Royston's father now.

Thanks.

Hi

The difference in age between two people will always remain the same.

You may use MD.

Consider 6 years ago.

Father ----- 3 units
Royston ----- 1 unit

Royston is 34 years younger than his father.

2 units ----- 34
1 unit ----- 17

6 years ago, his father was 51 years old.

Therefore now, he is (51+6) or 57 years old.

Best wishes

[ginangly]

Thanks Tianzhu.

[bcmum]

Hi, Pls help me with below questions.


Q1. John has some rats and some cages.
If he places one rat in each cage, there will be one rat without a cage.
If he places two rats in each cage, four cages will be empty.
How many rats does John have?

Q2. 16 tennis balls are divided into 4 groups, each with a different number of balls. What is the smallest possible number of balls in the biggest group?

Q3. Jack threw five darts at this board\t
\t\t\t\t
\t\t16\t\t
\t\t8\t\t
\t\t4\t\t
\t\t2\t\t
\t\t1\t\t
\t\t\t\t
\twhich of these scores is not possible?
\t\t\t\t
\t29\t39\t49\t59


Thank you.

[tianzhu]

Hi


The answers are

Q1) 10 rats
Q2) 6
Q3) 59

Best wishes

[bcmum]

Hi Tianzhu,


I would appreciate if you can advise on the solutions to obtain the answers as i am totally clueless how to solve them.

Thanks.

[Funz]

tianzhu:

cathycho:

Can someone help me with this question?


Mr salam haas 17 cats and birds in total. If he counted 44 legs in all, how many birds are there?

Hi

The numbers are small.P3 kids may use Guess and Check.

You may also use “Make a Supposition”

Assume all were cats, we’ve 17*4 ------ 68

Cat ----- 4 legs
Bird ----- 2 legs

Difference in number of legs between a cat and a bird ------ 2

68 – 44 ----- 24
24/2 ------ 12

12 birds

(5 cats)

For more practice, please visit pg 25-27 of this link.

http://www.kiasuparents.com/kiasu/forum/viewtopic.php?f=67&t=25121&start=240

Best wishes

DD encountered this types of question before. Though she has been shown how to solve them, I have no idea how to explain to her the rationale behind each step. Without understanding, if there should be any variation to this question, she will not be able to solve it. I have been trying to figure out how to explain to her but simply cannot wrap my head around it. So need help here.

Many thanks!!!

[jwxh]

Can someone please help me with this question:

A +B = 120
A - B = 48
Find the value of A.
Thanks

[tianzhu]

bcmum:

Hi Tianzhu,


I would appreciate if you can advise on the solutions to obtain the answers as i am totally clueless how to solve them.

Thanks.

Hi

Where are those questions from?

Those questions appear to be more like puzzles and brain teasers. They are not the types of typical questions found in past years papers.

Best wishes

[tianzhu]

jwxh:

Can someone please help me with this question:

A +B = 120
A - B = 48
Find the value of A.
Thanks

Hi

For P3, a neat way is to use MD.

A - B = 48 ------ This means A is 48 more than B.

Draw a rectangular bar to show A.

Draw another bar, a shorter one, to show B.

Bar A is longer than Bar B by 48.

So, you’ll have
(B + 48) + B ------ 120

B + B ------ 72
B ----- 36

A ----- 48 + 36 -------120

Best wishes

[jwxh]

thanks Tianzhu