Q&A - P4 Math

[chloecube]

Maths is interesting and fun if we can grab the concepts. its challenging and fun solving them

but i find it hard to put it across to my kids sometimes, they dun seem to understand or see it at my level

[elisammom]

tianzhu:

elisammom:

I used the guess and check method but the answer is not right.

The correct answer is 36, just like chloecube done.

I like to know why guess and check method is wrong in this question. Thanks

Hi

Yes, you may use GC.

For every 4 beads that A has, B has 2 more beads than her; this means if A has 4 beads, B has 6 beads.

Try it and you should arrive at 24 beads (A) and 36 beads(B).

A common method used by students is “Grouping concept”.

Another way, observe that for every incremental step, there is a difference of 10 beads (total number)

4, 6 ----- 10
8, 12 ------ 20

We are looking for 60.

60 is 6 times as many as 10

Hence multiply initial numbers by 6.

4*6 -----24
6*6 ------ 36

Best wishes

Thanks tianzhu
Ops I make a cal error;( yes now I see it;)

[Cheerfuldad]

Hi all,


Please help!

Q. There are some chickens and horses at a farm. Altogether, there are 41 heads and 118 leags. How many chickens are there?

TIA

[snowball]

1st step :

find the different ( 4 legs - 2 legs) = 2 legs

2nd step :
assume all 41 heads belongs to the animal that has the lesser no. of legs ie.chickens

thus, 41 heads x 2 legs = 82 legs

3rd step:
118 legs - 82 legs = 18 ( this is the no. of horse )

final step:
41-18=23 ( this is the no. of chickens )

[Mychildren]

Hi, snowball, the third step 118-82 = 36 why is it 18?


Hi, cheerfuldad, I used guess and check:
Chicken21x2=42 Horse20x4 =80 Total heads 41 but legs 122 so not correct.
Chicken22x2=44 Horse19x4=76 Total heads 41 but legs 120 so not correct.
Chicken23x2=46 Horse18x4=72 Total heads 41 and legs 118 so this is the answer.

[snowball]

snowball:

1st step :

find the different ( 4 legs - 2 legs) = 2 legs

2nd step :
assume all 41 heads belongs to the animal that has the lesser no. of legs ie.chickens

thus, 41 heads x 2 legs = 82 legs

3rd step: sorry, overlooked a step
118 legs - 82 legs = 36
36 divide by the difference ie = 2 , to get 18 ( this is the no. of horse )

final step:
41-18=23 ( this is the no. of chickens )

i used to use \"guess n check\" method, but sometimes my girl failed to get the correct guess even after the 4th or 5th attempt, so i switched to the above method :imcool:

[kaimono]

Pls help to solve this problem using units. thanks

There were twice as many blue clips as yellow clips in the box.
After giving away 66 blue chips and 8 yellow clips, there were thrice as many yellow clips as blue clips left in the box.
How many clips were there in the box at first?

[MathIzzzFun]

Cheerfuldad:

Hi all,


Please help!

Q. There are some chickens and horses at a farm. Altogether, there are 41 heads and 118 leags. How many chickens are there?

TIA

Hi

using area model, which is basically the assumptive method in model drawing...

http://www.flickr.com/photos/62167097@N02/6963704884/in/photostream

cheers.

[MathIzzzFun]

kaimono:

Pls help to solve this problem using units. thanks

There were twice as many blue clips as yellow clips in the box.
After giving away 66 blue chips and 8 yellow clips, there were thrice as many yellow clips as blue clips left in the box.
How many clips were there in the box at first?

Hi

you can use MD, or units method.

In the end,
Blue chips --> 2 units
Yellow chips --> 6 units ... since thrice as many yellow as blue chips.

At first,
Blue chips --> 2 units + 66
Yellow chips --> 1 unit + 33 .. since twice as many blue as yellow

Comparing yellow chips, before and after:
1 unit + 33 - 8 = 6 units
5 units --> 25, 1 unit --> 5

At first,
blue chips --> 2 x 5 + 66 = 76
yellow chips --> 5 + 33 = 38
total --> 114 blue & yellow chips

cheers.

[kaimono]

Thanks MathIzzzFun