Q&A - P3 Math

[HAPPYH]

bluesclue:

Hi HappyH,
Thanks for checking back and confirm.

You are welcome.

[vividlaurel]

Hi,


Can anyone help with this problem. The answer should be got using Heuristics.

Johnny had 30 ml more orange juice than Chloe at first. After Johnny drank 180 ml of orange juice, Chloe had twice as much orange juice as Johnny. How much orange juice did Johnny have at first?

TIA

[HAPPYH]

vividlaurel:

Hi,


Can anyone help with this problem. The answer should be got using Heuristics.

Johnny had 30 ml more orange juice than Chloe at first. After Johnny drank 180 ml of orange juice, Chloe had twice as much orange juice as Johnny. How much orange juice did Johnny have at first?

TIA

Is the answer 330?

180-30=150
150+150+30=330

Is this answer correct?

[vividlaurel]

Thanks HappyH,


Yes, that is the correct answer. I finally figured it out after posting it here.

HAPPYH:

vividlaurel:

Hi,

Can anyone help with this problem. The answer should be got using Heuristics.

Johnny had 30 ml more orange juice than Chloe at first. After Johnny drank 180 ml of orange juice, Chloe had twice as much orange juice as Johnny. How much orange juice did Johnny have at first?

TIA

Is the answer 330?

180-30=150
150+150+30=330

Is this answer correct?

[HAPPYH]

vividlaurel:

Thanks HappyH,


Yes, that is the correct answer. I finally figured it out after posting it here.

HAPPYH:

[quote=\"vividlaurel\"]Hi,

Can anyone help with this problem. The answer should be got using Heuristics.

Johnny had 30 ml more orange juice than Chloe at first. After Johnny drank 180 ml of orange juice, Chloe had twice as much orange juice as Johnny. How much orange juice did Johnny have at first?

TIA

Is the answer 330?

180-30=150
150+150+30=330

Is this answer correct?

[/quote]Yeh, finally got something correct

[vividlaurel]

LOL! I know the feeling! Was so happy when I got the answer. Isn’t it weird when P3 Maths is beyond you…

[HAPPYH]

vividlaurel:

LOL! I know the feeling! Was so happy when I got the answer. Isn't it weird when P3 Maths is beyond you....

:oops: But it is true.

[mwchua]

For multiplication of fraction, I started off by teaching my girl: numerator * numerator, denominator * denominator, e.g. 1/2 * 20 = 20/2 = 10


But the cancel way can also be taught, 1/2 * 20 since 2 and 20’s common divisor is 10.

I am just worried that the kid will get confused…But if I stick to numerator * numerator, denominator * denominator way, then if the number gets too big, this method will be very long-winded…

How do you all usually teach fraction fundamentals?

Thanks.

[HAPPYH]

mwchua:

For multiplication of fraction, I started off by teaching my girl: numerator * numerator, denominator * denominator, e.g. 1/2 * 20 = 20/2 = 10


But the cancel way can also be taught, 1/2 * 20 since 2 and 20's common divisor is 10.

I am just worried that the kid will get confused....But if I stick to numerator * numerator, denominator * denominator way, then if the number gets too big, this method will be very long-winded....

How do you all usually teach fraction fundamentals?

Thanks.

Sorry. Just to clarify. You are trying to explain 1/2 of 20, is it?

[jershejos]

I guess your kid needs to understand common factors before doing cross cancellation.

Found some website regards to this, hope it helps.
http://mathtrain.tv/play.php?vid=88
http://www.lessonpathways.com/Pathways/Detail?path=%2F05_Math%2FYear_5_Math_Guided_Journey%2F15Multiplying_and_Canceling
http://www.mff.org/mmc/cross_cancel_frogs.pdf