Q&A - P3 Math

[Nebbermind]

tianzhu:

Hi


Good Morning.

Hope this helps.

Best wishes.

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Shdn't delson have 900 + 3U?

[tianzhu]

Nebbermind:

Shdn't delson have 900 + 3U?

Hi Nebbermind

Thank you.

I made a mistake earlier.

I've revised my solution.

Best wishes

http://farm6.static.flickr.com/5293/5531176959_3d8a984c85_z.jpg\">

[tianzhu]

usaik:

Hi tianzhu,

I really admire :salute: and appreciate your efforts!! :thankyou:

Regards

Hi usaik

You're welcome.

Best wishes

[concerned1970]

Hi Tianzhu, hope u can help me to solve all these maths pb sums with models if possible.


1) Fuhua has $30 more than Liming. If Fuhua spends $42 and Liming spends $10, who will have more money left? How much more?

2) Mr Lu had 20 currency notes. Some of them were five-dollar notes and the rest were twenty-dollar notes. The total amount was $220. How many notes of each kind were there?

3) A bill of $72 was paid with $10, $5 and $1 notes, if 13 notes were used for payments, how many notes of each kind were used?

4) 2 mangoes cost as much as 3 oranges. The cost of 2 mangoes and 3 oranges are $2. What is the cost of 12 oranges?

5) Mr Li bought 100 fish for $100. He paid $3 for each big fish and $1 for 3 small fish. How many big fish and how many small fish did Mr Li buy?

[tianzhu]

concerned1970:

Hi Tianzhu, hope u can help me to solve all these maths pb sums with models if possible.

2 mangoes cost as much as 3 oranges. The cost of 2 mangoes and 3 oranges are $2. What is the cost of 12 oranges?

Hi concerned1970

Good Morning.

First thing first, are these questions from P3 or P4?

MD helps students to “see” Maths, it offers a pictorial representation. However I wish to emphasise that it’s not the only method to solve primary maths questions. You may also wish to consider other heuristics as well.

Heuristics such as Guess and Check and Make a Systematic List are useful especially for lower primary Maths where the numbers are smaller.

I’ll take the question on mangoes and oranges first, simply because I love Thai Mango Sticky Rice.NTUC supermarkets offer good buys for Thai mangoes presently.

I don’t think MD is necessary for this particular question.

2 mangoes ------ 3 oranges
2 mangoes and 3 oranges ------- $2.

This means

6 oranges ------- $2
Therefore 12 oranges ------- $4 (2*2)

If the question is in this manner, then probaly MD is helpful.Try it.

2 apples cost as much as 3 oranges. The cost of 2 oranges and 5 apples are $5.70. What is the cost of each fruit?

Best wishes

[tianzhu]

Hi concerned1970


The solution for your first question.

As for Q2, Q3 and Q5, you may do them using GC or Systemmatic Listing. For Q2 and Q5, you may also consider \"Make a Supposition\" (Assumption Method).Try them out first.

Best wishes.

http://farm6.static.flickr.com/5018/5533751356_97e2a3a3b1_z.jpg\">

[concerned1970]

Gd afternoon, it is P3 ques. Tysm for yr generous help. I know the ans to all ques but my son still doesn't get it when I tried to explain it to him. That's why I need yr help with yr models. So sry to trouble u.

[tianzhu]

concerned1970:

Gd afternoon, it is P3 ques. Tysm for yr generous help. I know the ans to all ques but my son still doesn't get it when I tried to explain it to him. That's why I need yr help with yr models. So sry to trouble u.

Hi concerned1970

You're welcome.

It’s important to know that MD is one of many heuristics in the primary maths syllabus. Besides MD, it’s good to consider other problem solving strategies as it offers students greater versatility in problem solving.

A student with a wider range of strategies is better able to adapt to challenges when he/she faces unfamiliar questions in examinations. Just like football, a team is able to change shape when dealing with different opponents.

A bill of $72 was paid with $10, $5 and $1 notes, if 13 notes were used for payments, how many notes of each kind were used?

For this question, it helps if a student is well versed in number bonds.

A little bit of planning helps to avoid unnecessary guesses.

The bill of 72 has a number bond of 60 and 12.
12 ------ 10+2 or 10+1+1 or 5+5+1+1, we are using 2 because we are dealing with multiples of $5 and $10.

So we need 2 $1 note, leaving a difference of $70 (72- 2 -----70)

You may start with GC or Listing

Set up a tabulated list with $10, $5 and $1 as headings.

Make calculated guesses to get a number of $10 and $5 notes (total number of 11 with a value of $70).

It shouldn’t be too tedious to arrive at 3 $10 notes and 8 $5 notes.

(3*10) ----- 30
(8*5) ----- 40
(2*1) ------ 2

Therefore we have 3 $10 notes, 8 $5 notes and 2 $1 notes.

Try out the other two questions, if you need any help, please let me know.

Best wishes

[concerned1970]

Hi Tianzhu, I got different ans for ques 3 (dollar notes). 3 $10, 8 $5 and 2 $1. Is there any other method to work out this pb sum besides guess and check method? I duno how to draw models for ques 2 and 5. Can you help me with the models drawings? Ty.

[teh_oh]

concerned1970:

5) Mr Li bought 100 fish for $100. He paid $3 for each big fish and $1 for 3 small fish. How many big fish and how many small fish did Mr Li buy?

Hi,
Is the answer
25 Big Fish and 75 Small Fish?

(while i still scratching my head, my child gave me this answer.......but he said he use trial and error. :oops:)