Q&A - P3 Math

[Oldschool]

cherrygal:

Oldschool:

[quote=\"angel\"]Amy and Betty shared 200 cookies. After Amy ate 30 cookies and Betty baked another 28 cookies, they had the same number of cookies. How many cookies did Betty have at first?

Sorry, can you kindly explain the rationale for this question? Got trouble understanding the model. Thanks[/quote]Hi,

Probably, this would be clearer.

http://i43.tinypic.com/9gym2w.jpg\">

Regards

[cherrygal]

Thanks oldschool but how did you get the value of U as 71? Can show the working before U = 71? Method of achieving 71 looks a bit different from what his teacher wanted yesterday. Will check once we get that practice paper back.


Is this possible? Thought I saw something like this in his paper.
200 - 30 - 28 = 142
142 / 2 = 71
U = 71

[Oldschool]

cherrygal:

Thanks oldschool but how did you get the value of U as 71? Can show the working before U = 71? Method of achieving 71 looks a bit different from what his teacher wanted yesterday. Will check once we get that practice paper back.


Is this possible? Thought I saw something like this in his paper.
200 - 30 - 28 = 142
142 / 2 = 71
U = 71

Hi,

Yep, just by working

U + 28 + 30 + U = 200
2U + 58 = 200
2U = 200 - 58
2U = 142
U = 71

Regards

[MathIzzzFun]

cherrygal:

Thanks oldschool but how did you get the value of U as 71? Can show the working before U = 71? Method of achieving 71 looks a bit different from what his teacher wanted yesterday. Will check once we get that practice paper back.


Is this possible? Thought I saw something like this in his paper.
200 - 30 - 28 = 142
142 / 2 = 71
U = 71

the solution is based on the standard comparison model which can be obtained as follows :

http://i39.tinypic.com/2z9k6xj.png\">

cheers.

[cherrygal]

Thanks MathsIzzFun! Yes, I think this is the model.

[SAHM_TAN]

Oldschool:

angel:

Amy and Betty shared 200 cookies. After Amy ate 30 cookies and Betty baked another 28 cookies, they had the same number of cookies. How many cookies did Betty have at first?

Hi,

http://i44.tinypic.com/2zgt1cp.jpg\">

Regards

Hi,

In this qn, the 200 cookies includes the 28 cookies that Betty baked later?

[Oldschool]

SAHM_TAN:

Oldschool:

[quote=\"angel\"]Amy and Betty shared 200 cookies. After Amy ate 30 cookies and Betty baked another 28 cookies, they had the same number of cookies. How many cookies did Betty have at first?

Hi,

http://i44.tinypic.com/2zgt1cp.jpg\">

Regards

Hi,

In this qn, the 200 cookies includes the 28 cookies that Betty baked later?[/quote]Hi,

Interesting.
If the question arises because of my poor MD presentation then I’m sorry.
You can scroll up for much clearer drawings.

Otherwise, at this level, mathematics is generally considered to be sequential in nature.
When it is communicated in words or orally, it must be clear.
Likewise, when it is interpreted, it must be logical.
Thus, it is important for both the communicator and the interpreter to recognize the framework for the passage of events. In other words, “sequencing activities in terms of time” – i.e. what come first, second and third or where is the starting and ending point.

In this question, the sentence “Amy and Betty shared 200 cookies” did not specify if they had 200 cookies “at first” or “in the end”. However, this sentence precedes the next sentence “After…..30 and ….28 cookies”. Therefore, following this sequence of description or chronological order, one would interpret that Amy and Betty had 200 cookies at first. Hence, it does not includes the 28 cookies baked by Betty thereafter.

Regards

[jolenekoh]

Thank you


Mr. Siva has 240 pens. He has 25 more purple pens than black pens. He has 40 fewer red pens than black pens. How many red pens does he have?

[peggy]

jolenekoh:

Thank you


Mr. Siva has 240 pens. He has 25 more purple pens than black pens. He has 40 fewer red pens than black pens. How many red pens does he have?

Is the answer 45 ?

[jolenekoh]

peggy:

jolenekoh:

Thank you


Mr. Siva has 240 pens. He has 25 more purple pens than black pens. He has 40 fewer red pens than black pens. How many red pens does he have?

Is the answer 45 ?

Sorry...I don't have the answer woh :scratchhead: