Q&A - P3 Math

[cathycho]

What is the fastest method to solve this type of question?


Darren has some 10-cent coins, 20-cent coins and 50-cent coins in his pocket that add up to $2. He has exactly 9 coins. How many 20-cent coins does he have?

[tianzhu]

cathycho:

What is the fastest method to solve this type of question?


Darren has some 10-cent coins, 20-cent coins and 50-cent coins in his pocket that add up to $2. He has exactly 9 coins. How many 20-cent coins does he have?

Hi

First, is this a multiple choice question where four options are available for students to choose?

The numbers are not too big, so it’ll not be tedious to arrive at an answer if choices are given.

If not, use “Systematic Listing”, it’s also not too tedious as we are dealing with small numbers.

The answer is 3 20-cent coins.

Best wishes

[HAPPYH]

cathycho:

What is the fastest method to solve this type of question?


Darren has some 10-cent coins, 20-cent coins and 50-cent coins in his pocket that add up to $2. He has exactly 9 coins. How many 20-cent coins does he have?

I really wonder why our children needs to know this. As long as they know the value of each coin and how to make certain amount, isn't fine? Sigh

[cathycho]

tianzhu:

cathycho:

What is the fastest method to solve this type of question?


Darren has some 10-cent coins, 20-cent coins and 50-cent coins in his pocket that add up to $2. He has exactly 9 coins. How many 20-cent coins does he have?

Hi

First, is this a multiple choice question where four options are available for students to choose?

The numbers are not too big, so it’ll not be tedious to arrive at an answer if choices are given.

If not, use “Systematic Listing”, it’s also not too tedious as we are dealing with small numbers.

The answer is 3 20-cent coins.

Best wishes

Yes, it's a multiple choice question. Thks.

[Taurus]

[Mod's note: threads merged]

Hi,

Anyone can help to explain how to get the answer:

Qns : When A is divided by 5, it gives a remainder. Which is the most possible pair of quotient (Q) and remainder (R) when A is divided by 5?

(1) Q = 5, R= 9
(2) Q = 6, R = 6
(3) Q = 5, R = 5
(4) Q = 6, R = 4

[BigDevil]

Hi, instead of starting a new thread for your question, please go to the http://www.kiasuparents.com/kiasu/forum/viewtopic.php?f=66&t=149 thread and post a reply there.


For this question, the answer is (4). In division, the remainder can never be equal or more than the divisor.

[e.011054chua]

Pls help me on this question.


In a class of 42 pupils, each boy received 3 stickers and each girl received 4 stickers from their teacher. Altogether the teacher gave out 154 stickers. How many girls were there in this class?

The answer is :
42 x 4 = 168
168-42 = 126
154-126 = 28

But I do not understand why 168-42 ?

[MathIzzzFun]

e.chua:

Pls help me on this question.


In a class of 42 pupils, each boy received 3 stickers and each girl received 4 stickers from their teacher. Altogether the teacher gave out 154 stickers. How many girls were there in this class?

The answer is :
42 x 4 = 168
168-42 = 126
154-126 = 28

But I do not understand why 168-42 ?

Hi
I think the answer provided is based on assumptive method... with 1 extra step.
Assume all are girls --> 3 x 42 = 126 (which is = 168 - 42)

The assumptive method can also be represented in form of area model ..

http://i43.tinypic.com/35a7ivo.png\">

cheers.

[Michaelia0816]

I also got a method, similar but more understanding!

Method: Assuming
Let us assume that all are boys
Time- 42x3=126
Minus- 154-126=28
Minus- 4-3=1
Divide- 28 divide 1=28
So the answer is 28.
remember TMMD method using assuming!

[peapot]

Oh! this method is abit like the 2 legs and 4 legs question.


I also have a question which I remember someone ask before. But I can’t understand why? Hope someone can explain.

Jeremy brought a sum of money to buy some pencils. If he buys 4 pencils, he would be left with $2. If he buys 5 pencils, he would need another $1.

How much is the cost of 1 pencil? and how much money did he have at first?