Q&A - P4 Math

[snowball]

John is 34 yrs old n his son is 4 yrs old now. In how many yrs time will John be 4 times as old as his son?

[BigDevil]

snowball:

There were twice as many men as women in the hall.

After 12 women had left the hall, there were thrice as many men as women who remained in the hall.
How many men were in the hall at first?

http://i49.tinypic.com/b83bbo.jpg\">

[BigDevil]

snowball:

John is 34 yrs old n his son is 4 yrs old now. In how many yrs time will John be 4 times as old as his son?

http://i45.tinypic.com/35mo0fk.jpg\">

[Nebbermind]

snowball:

how to explain to DD ;


3/5 divide by 3 is the same as 3/5 multiply by 1/3 ???

I think you should teach her the concept of fractions and 3/5 is actually

1/5 + 1/5 + 1/5

and if divided by 3, u get 1/5.

The answer may be ths same but for younger kids, it's good for they to be able to visualize why they are the same.

Same for multipication. 3 of 5 and 5 of 3 means very different things even thought their answers are the same.

[snowball]

BigDevil:

snowball:

There were twice as many men as women in the hall.

After 12 women had left the hall, there were thrice as many men as women who remained in the hall.
How many men were in the hall at first?

http://i49.tinypic.com/b83bbo.jpg\">

:thankyou: :please:
for this type of questions, how do we see (beginning) how many units to draw in the model? eg, for the above qn, 6units to draw for the men :?

[snowball]

Nebbermind:

snowball:

how to explain to DD ;


3/5 divide by 3 is the same as 3/5 multiply by 1/3 ???

I think you should teach her the concept of fractions and 3/5 is actually

1/5 + 1/5 + 1/5

and if divided by 3, u get 1/5.

The answer may be ths same but for younger kids, it's good for they to be able to visualize why they are the same.

Same for multipication. 3 of 5 and 5 of 3 means very different things even thought their answers are the same.

Dear Nebbermind, using your suggestion above ( 1/5 +1/5+ 1/5) is indeed a very simple but useful explaination .

However, how do i explain;

3/8 divide by 3/5 is = 3/8 x 5/3 :?

[Nebbermind]

Snowball


See if http://www.homeschoolmath.net/teaching/f/division_fractions.php makes any sense to you.

[snowball]

Nebbermind:

Snowball


See if http://www.homeschoolmath.net/teaching/f/division_fractions.php makes any sense to you.

:thankyou: EASIER NOW! :rahrah:

[BigDevil]

snowball:

:thankyou: :please:
for this type of questions, how do we see (beginning) how many units to draw in the model? eg, for the above qn, 6units to draw for the men :?

You will realise what model to draw if you can think of this question in fractions.

At first, there were twice the number of men as women. That's the same as saying number of women is 1/2 of men.

Likewise, at the end, number of women is 1/3 of men.

Changing to same denominator, you get 3/6 at first, and 2/6 at the end.
You can then proceed to solve the problem with fractions (1/6 = 12),
or draw the model with 6 units for men.

You can also draw the following alternate model for this question without realising you need to draw 6 units for men:
http://i48.tinypic.com/iznno9.jpg\">

[snowball]

BigDevil:

snowball:

John is 34 yrs old n his son is 4 yrs old now. In how many yrs time will John be 4 times as old as his son?

http://i45.tinypic.com/35mo0fk.jpg\">

:scratchhead: why 3u is 30? :scratchhead: :?