Q&A - PSLE Math

[mathnoobs]

tianzhu:

mathnoobs:

Hi Tianzhu,

this question threw me off, I thought I had understood this type of questions:

Don spent $268 of his savings on a camera and 3/8 of the remainder on a pair of shoes. Then, he bought a bag for $62 and had 1/4 of his savings left. How much savings did Don have at first?

over here, the 1/4 of his savings refers to the original savings Don had, before he spent any money.

however in this question,
Nicole had saved a certain amount of money. In January, she spent 30% of her savings. In February, she managed to save 1/5 of the amount of money she had left. Then she purchased 8 pens at $3.95 each. When she heard heard her parents were going on a tour, she gave them 3/8 of the amount she had left. In March, she managed to save 40% of her savings left. Finally she had $6219.85 in the bank.
A) how much money did she give to her parents ?
B) how much was her original saving in the bank ?

the 40% of her savings refers, not to the original savings Nicole had at the start, but the savings in March.

Both the Don question and the Nicole question uses the keywords, of his/her savings. In the Don question, the savings (1/4) referred to the savings at the start, while in the Nicole question, the savings (40%) referred to the savings in March, not at the start. Shouldn't both questions refer to savings at the start ? so that the interpretation is consistent ?
Or if one follows the Nicole example, then Don's question should have the 1/4 savings refer to the savings after the shoes were bought, not at the start.

Hi mathnoobs

Good Morning.

I think you've missed out the word left in the second question.

Best wishes

Good morning Tianzhu
thank you for replying to my questions early in the morning. Wishing you a good day ahead.

actually both questions have the word left, that's what really got me confused:

Don spent $268 of his savings on a camera and 3/8 of the remainder on a pair of shoes. Then, he bought a bag for $62 and had 1/4 of his savings left. How much savings did Don have at first?

Nicole had saved a certain amount of money. In January, she spent 30% of her savings. In February, she managed to save 1/5 of the amount of money she had left. Then she purchased 8 pens at $3.95 each. When she heard heard her parents were going on a tour, she gave them 3/8 of the amount she had left. In March, she managed to save 40% of her savings left. Finally she had $6219.85 in the bank.
A) how much money did she give to her parents ?
B) how much was her original saving in the bank ?

[tianzhu]

mathnoobs:

Good morning Tianzhu
thank you for replying to my questions early in the morning. Wishing you a good day ahead.

actually both questions have the word left, that's what really got me confused:

Don spent $268 of his savings on a camera and 3/8 of the remainder on a pair of shoes. Then, he bought a bag for $62 and had 1/4 of his savings left. How much savings did Don have at first?

Nicole had saved a certain amount of money. In January, she spent 30% of her savings. In February, she managed to save 1/5 of the amount of money she had left. Then she purchased 8 pens at $3.95 each. When she heard heard her parents were going on a tour, she gave them 3/8 of the amount she had left. In March, she managed to save 40% of her savings left. Finally she had $6219.85 in the bank.
A) how much money did she give to her parents ?
B) how much was her original saving in the bank ?

Hi

In the first question, all the expenses are deducted from the initial or original savings.

Imagine Don were shopping in Takashimaya; he started with an initial amount (612).He paid 268 for a camera. He spent $129 on a pair of shoes and $62 on a bag. After his shopping, he sat down in the food court and counted his remaining money which amounted to 1/4 of the original savings.

In the second question, we have a sequence of events from Jan to March.

In March, she managed to save 40% of her savings left.

This refers to 40% of her savings in March.

Best wishes

[mathnoobs]

tianzhu:

mathnoobs:

Good morning Tianzhu
thank you for replying to my questions early in the morning. Wishing you a good day ahead.

actually both questions have the word left, that's what really got me confused:

Don spent $268 of his savings on a camera and 3/8 of the remainder on a pair of shoes. Then, he bought a bag for $62 and had 1/4 of his savings left. How much savings did Don have at first?

Nicole had saved a certain amount of money. In January, she spent 30% of her savings. In February, she managed to save 1/5 of the amount of money she had left. Then she purchased 8 pens at $3.95 each. When she heard heard her parents were going on a tour, she gave them 3/8 of the amount she had left. In March, she managed to save 40% of her savings left. Finally she had $6219.85 in the bank.
A) how much money did she give to her parents ?
B) how much was her original saving in the bank ?

Hi

In the first question, all the expenses are deducted from the initial or original savings.

Imagine Don were shopping in Takashimaya; he started with an initial amount (612).He paid 268 for a camera. He spent $129 on a pair of shoes and $62 on a bag. After his shopping, he sat down in the food court and counted his remaining money which amounted to 1/4 of the original savings.

In the second question, we have a sequence of events from Jan to March.

In March, she managed to save 40% of her savings left.

This refers to 40% of her savings in March.

Best wishes

Hi Tianzhu
thank you again for answering my queries. Sorry for being so tiresome. It's just that if I don't clarify this, in future, if I see the same type of question, I would not know how to interpret these type of questions, let alone solve it.
If there was some clue on how to interpret this (as you can see, the interpretation \"of his/her savings left\" is different in the 2 questions), it would be very helpful.

In the Don question, it can also be broken down into a sequence of events, just like the Nicole question. In fact, that was how I interpreted it.
The camera purchase was one event, the shoes purchase was another event followed by the bag, a third event.

In the shoe purchase, Don spent \"3/8 of the remainder on a pair of shoes\". The purchase was 3/8 of the remainder, it was not linked to the original savings. After that, that problem said \"then he bought a bag for $62\", which I interpreted it to mean subsequently, since the word \"then\" is there, I interpreted that he paid the $62 out of the remainder and had 1/4 of the remainder left.
Now, normally I would not have interpreted it this way, ie. 1/4 of the remainder, because it said \"1/4 of the savings left\". I would interpret the savings to mean the orignal savings.

However, because of the Nicole question, which also said the same thing \".... of the savings left\", and that was interpreted as the savings left in March, I thought that the Don question should also be interpreted in the same way, afterall they shared the same keywords, and the Don question said \"3/8 of the remainder\" which does constitute a sperate event.

[tianzhu]

mathnoobs:

tianzhu:

[quote=\"mathnoobs\"]
Good morning Tianzhu
thank you for replying to my questions early in the morning. Wishing you a good day ahead.

actually both questions have the word left, that's what really got me confused:

Don spent $268 of his savings on a camera and 3/8 of the remainder on a pair of shoes. Then, he bought a bag for $62 and had 1/4 of his savings left. How much savings did Don have at first?

Nicole had saved a certain amount of money. In January, she spent 30% of her savings. In February, she managed to save 1/5 of the amount of money she had left. Then she purchased 8 pens at $3.95 each. When she heard heard her parents were going on a tour, she gave them 3/8 of the amount she had left. In March, she managed to save 40% of her savings left. Finally she had $6219.85 in the bank.
A) how much money did she give to her parents ?
B) how much was her original saving in the bank ?

Hi

In the first question, all the expenses are deducted from the initial or original savings.

Imagine Don were shopping in Takashimaya; he started with an initial amount (612).He paid 268 for a camera. He spent $129 on a pair of shoes and $62 on a bag. After his shopping, he sat down in the food court and counted his remaining money which amounted to 1/4 of the original savings.

In the second question, we have a sequence of events from Jan to March.

In March, she managed to save 40% of her savings left.

This refers to 40% of her savings in March.

Best wishes

Hi Tianzhu
thank you again for answering my queries. Sorry for being so tiresome. It's just that if I don't clarify this, in future, if I see the same type of question, I would not know how to interpret these type of questions, let alone solve it.
If there was some clue on how to interpret this (as you can see, the interpretation \"of his/her savings left\" is different in the 2 questions), it would be very helpful.

In the Don question, it can also be broken down into a sequence of events, just like the Nicole question. In fact, that was how I interpreted it.
The camera purchase was one event, the shoes purchase was another event followed by the bag, a third event.

In the shoe purchase, Don spent \"3/8 of the remainder on a pair of shoes\". The purchase was 3/8 of the remainder, it was not linked to the original savings. After that, that problem said \"then he bought a bag for $62\", which I interpreted it to mean subsequently, since the word \"then\" is there, I interpreted that he paid the $62 out of the remainder and had 1/4 of the remainder left.
Now, normally I would not have interpreted it this way, ie. 1/4 of the remainder, because it said \"1/4 of the savings left\". I would interpret the savings to mean the orignal savings.

However, because of the Nicole question, which also said the same thing \".... of the savings left\", and that was interpreted as the savings left in March, I thought that the Don question should also be interpreted in the same way, afterall they shared the same keywords, and the Don question said \"3/8 of the remainder\" which does constitute a sperate event.[/quote]Hi

I am sorry; I can’t answer your question in detail now.

Just curious, are these questions from the mummy or from your child?

Is your child in P5 or P6?

If your child is in P5, higher order questions on remainder concept may not be covered by his/her teacher yet as the year is still quite young.

If you have a copy of Challenging Maths Made Easy, I suggest you look at the chapter on Remainder Concept.

Perhaps you may want to work out the answer based on the way you described. You may appreciate the situation better.

Best wishes

[mathnoobs]

tianzhu:

Hi

I am sorry; I can’t answer your question in detail now.

Just curious, are these questions from the mummy or from your child?

Is your child in P5 or P6?

If your child is in P5, higher order questions on remainder concept may not be covered by his/her teacher yet as the year is still quite young.

If you have a copy of Challenging Maths Made Easy, I suggest you look at the chapter on Remainder Concept.

Perhaps you may want to work out the answer based on the way you described. You may appreciate the situation better.

Best wishes

Hi Tianzhu
my child is in P5. The questions are mine. I have to be clear before I can teach my child or else it's the blur teaching the blur.
I do have a copy of the Challenging Maths. However, they don't really talk about question interpretation. The questions there are more straight forward in terms of interpretation.

I did work out the Don problem sum with the 1/4 based on the remainder savings and it came out as a decimal number, so that can't be right.

[tianzhu]

mathnoobs:

Hi Tianzhu
my child is in P5. The questions are mine. I have to be clear before I can teach my child or else it's the blur teaching the blur.
I do have a copy of the Challenging Maths. However, they don't really talk about question interpretation. The questions there are more straight forward in terms of interpretation.

I did work out the Don problem sum with the 1/4 based on the remainder savings and it came out as a decimal number, so that can't be right.

Hi

It’s good to know you found the questions in Challenging Maths more straight forward in terms of interpretation. It shows you have grasped the concepts well.

Your child is in P5, those two questions are for P6, so he doesn’t know them now because he hasn’t been taught yet. Once he learns from his teacher, he’ll know how to do them. So don’t worry too much now.

I am sure you are familiar with this question.

Mrs Jaya spent $162 on a present for her husband. She spent 5/11 of the remaining money on a purse for herself. If she had 3/7 of her money left, how much money did Mrs Jaya have a first?

Please refer to an example of a similar question under 1.2, page 3 of CM.

Now let us look at Don’s question.

Don spent $268 of his savings on a camera and 3/8 of the remainder on a pair of shoes. Then, he bought a bag for $62 and had 1/4 of his savings left. How much savings did Don have at first?

Please refer to my solution to Rice last night.

Don had $612 at first. He went on to spend $268 on a camera, leaving a remaining amount of $129 (3/8 of $344).Then he bought a bag for $62, leaving a remaining amount of $153 (1/4 of savings left).

For the Nicole question,please read sentence by sentence and understand the context.

I think you'll find it clear enough to know that the 40% of the savings is based on the remaining amount of her money in March and not on her original savings in Jan.

Best wishes

[mathnoobs]

tianzhu:

mathnoobs:

Hi Tianzhu
my child is in P5. The questions are mine. I have to be clear before I can teach my child or else it's the blur teaching the blur.
I do have a copy of the Challenging Maths. However, they don't really talk about question interpretation. The questions there are more straight forward in terms of interpretation.

I did work out the Don problem sum with the 1/4 based on the remainder savings and it came out as a decimal number, so that can't be right.

Hi

It’s good to know you found the questions in Challenging Maths more straight forward in terms of interpretation. It shows you have grasped the concepts well.

Your child is in P5, those two questions are for P6, so he doesn’t know them now because he hasn’t been taught yet. Once he learns from his teacher, he’ll know how to do them. So don’t worry too much now.

I am sure you are familiar with this question.

Mrs Jaya spent $162 on a present for her husband. She spent 5/11 of the remaining money on a purse for herself. If she had 3/7 of her money left, how much money did Mrs Jaya have a first?

Please refer to an example of a similar question under 1.2, page 3 of CM.

Now let us look at Don’s question.

Don spent $268 of his savings on a camera and 3/8 of the remainder on a pair of shoes. Then, he bought a bag for $62 and had 1/4 of his savings left. How much savings did Don have at first?

Please refer to my solution to Rice last night.

Don had $612 at first. He went on to spend $268 on a camera, leaving a remaining amount of $129 (3/8 of $344).Then he bought a bag for $62, leaving a remaining amount of $153 (1/4 of savings left).

For the Nicole question,please read sentence by sentence and understand the context.

I think you'll find it clear enough to know that the 40% of the savings is based on the remaining amount of her money in March and not on her original savings in Jan.

Best wishes

Hi Tianzhu
thank you very much for spending so much time to explain the concepts to me. I really do appreciate it.
I guess the only way reinforce the concept will be to do more such similar questions. The Mrs Jaya question helped. I wonder if there's more of the Nicole type of questions.
Anyway, I have to move on to other question types. There's just so much to cover.
thanks again and have a great evening.

[tianzhu]

mathnoobs:

Hi Tianzhu
thank you very much for spending so much time to explain the concepts to me. I really do appreciate it.
I guess the only way reinforce the concept will be to do more such similar questions. The Mrs Jaya question helped. I wonder if there's more of the Nicole type of questions.
Anyway, I have to move on to other question types. There's just so much to cover.
thanks again and have a great evening.

Hi

You’re welcome.

You’re definitely not a “blur” mummy like you mentioned. On the contrary, the way you dissected the points in the questions and your ability to ask penetrating questions shows an enthusiastic and dynamic mummy.

The fact that you’re asking questions here suggests that you son is coping without tuition.

P5’s syllabus is rather heavy. It’s a quantum leap and students will be introduced to new topics like ratios and percentages.

Perhaps, it may be a little bit too early to introduce those two questions to your child now. Let the school teacher teach and reinforce the concepts first.

Sometimes, backwards is a way to move someone forward.

As for more questions similar to Nicole’s type, I am afraid I am of no help. As you know, I am a post PSLE dad. I have not been reading primary maths books and test papers for a few years liao. Please seek help from current primary school students or their parents.

You may also refer to testpapers from top schools to see if can find similar questions.

http://www.orlesson.org/orp/MathExam.html
http://test-paper.info/

Have a great weekend.

Best wishes

[mathnoobs]

tianzhu:

You’re welcome.

You’re definitely not a “blur” mummy like you mentioned. On the contrary, the way you dissected the points in the questions and your ability to ask penetrating questions shows an enthusiastic and dynamic mummy.

thank you for the kind words, Tianzhu.
It made my day. :rahrah:
have a great week.

[Winx5015]

Hi,


Can anyone help me with these questions?

Q1). Calvin had 288 more sweets than Elizabeth. After Calvin gave away 1/6 of his sweets and Elizabeth gave away 3/4 of her sweets, Calvin had 324 more sweets than Elizabeth. How many sweets did Calvin have at first?

Q2). Mrs Lee baked 60 more chocolate pies than banana pies. After giving away 2/5 of the chocolate pies and 3/4 of the banana pies, she had 64 more chocolate pies than banana pies left. How many chocolate pies did she bake at first?

Thanks!