P4 Fractions Problem sum

[zac's mum]

Here’s my answer for the first one:


https://postimg.cc/Z0Qbspbt

[zac's mum]

Second one, this is my basic model, but it shouldn’t be the way for P4 cos they can’t divide by 41 units without calculator.


Consulting my SIL who’s a math tutor.

https://postimg.cc/XrQDxcW9

[zac's mum]

Ok my SIL has replied. My model is correct, I have updated to indicate the units.


I’ve included her reply. Use lowest common multiple to manipulate the equal parts. Beginners use model method but the more advanced kids can skip model to save time.

Don’t need calculator. Use the concept that “division is repeated subtraction”/“multiplication is repeated addition” to work out that 41+41+41=123. So 1U=1230 divided by 41=$30. 9U=9x30=$270.

I checked my P4 Onsponge book and this heuristic method is taught on page 95 “Numerators the Same”. SIL said tutors more commonly refer to it as \"Equating Numerators\".

https://postimg.cc/4Y1Rm6kj
https://postimg.cc/qthfQ9CH
https://postimg.cc/4KzDrpwW

[kiasuchabo]

zac's mum\" post_id=\"1987339\" time=\"1595496374\" user_id=\"53606:[quote=\"zac's mum\" post_id=1987339 time=1595496374 user_id=53606]
Ok my SIL has replied. My model is correct, I have updated to indicate the units.

I’ve included her reply. Use lowest common multiple to manipulate the equal parts. Beginners use model method but the more advanced kids can skip model to save time.

Don’t need calculator. Use the concept that “division is repeated subtraction”/“multiplication is repeated addition” to work out that 41+41+41=123. So 1U=1230 divided by 41=$30. 9U=9x30=$270.

I checked my P4 Onsponge book and this heuristic method is taught on page 95 “Numerators the Same”. SIL said tutors more commonly refer to it as \"Equating Numerators\".

https://postimg.cc/4Y1Rm6kj
https://postimg.cc/qthfQ9CH
https://postimg.cc/4KzDrpwW[/quote]

Thanks Zac's mum again!!! :rahrah: You have the correct answers:)
First one your working exactly the same as the Gradual Difficulty book

second one your answer is correct too...
sounds very chim omg :? i need to go and study about your answer, hopefully my brain can be half as good as yours

THANKS A MILLION!

[zac's mum]

No worries dear. Good thing you brought this kind of questions to my attention! My DS school is definitely not teaching them this type of questions…yet. I have no idea is it due to the kids are not ready yet? Or do they even intend to teach it, like are they waiting for P5??


SIL is an experienced tutor, she has been thru so many PSLEs with her students, so she is kancheong that my DS should know all this liao. I don’t know if other schools expect it at P4. I am super sad that she is retiring from tutoring after this PSLE, does not want to take on my DS as her future pupil.

Anyway, this kind of question, once u get the lightbulb moment, u will remember it for life. My son could grasp it. I think u and your DS can too, jia you!

[kiasuchabo]

Zac's mum,

may i ask, for second question, method 2, how to change the original 5/8 and 2/5 to 10/16 and 10/25 respectively?

:?

[zac's mum]

If u are able to “see” from the model, the numerators 5 and 2 are the same value (same length in the model).


So use the Lowest Common Multiple of 5 and 2 (ie. 10) to make the fractions have the equivalent numerator 10.

The denominator must be multiplied by the same multiple (as the numerator) also.

[samlarson]

[quote]
Ok my SIL has replied. My model is correct, I have updated to indicate the units.

I’ve included her reply. Use lowest common multiple to manipulate the equal parts. Beginners use model method but the more advanced kids can skip model to save time.

Don’t need calculator. Use the concept that https://promoneysavings.com/need-money-now/ “division is repeated subtraction”/“multiplication is repeated addition” to work out that 41+41+41=123. So 1U=1230 divided by 41=$30. 9U=9x30=$270.

I checked my P4 Onsponge book and this heuristic method is taught on page 95 “Numerators the Same”. SIL said tutors more commonly refer to it as \"Equating Numerators\".

https://postimg.cc/4Y1Rm6kj
https://postimg.cc/qthfQ9CH
https://postimg.cc/4KzDrpwW[/quote]I'm sorry for the off-topic post but your handwriting looks amazing