Q&A - P4 Math

[tianzhu]

chloecube:

Need help :

Hito baked 10 cookies. Tom baked 60 more than Hito. Peter baked many more cookies and gave them each an equal number of cookies. Now Hito has 1/4 as many cookies as Tim. How many cookies did Peter give to each of them?
I found the answer is 10 by guessing. How do I explain to DS correctly?

Hi

Picture this.

Tom baked 60 more cookies than Hito.

Imagine Tom having 70 cookies and Hito having 10 cookies. The difference in the number of cookies was 60.

Peter gave them an equal number of cookies. Since an equal number of cookies were given to Tom and Hito, the difference in the number of cookies between Tom and Hito remained the same at 60.

P4 kids may use MD.

So 3 units ----- 60
1 unit ----- 20

20-10 ------ 10

Peter gave 10 cookies to each of them.

Best wishes

[chloecube]

I understand now. Thks tianzhu

[tianzhu]

chloecube:

Fara had 2/3 as many stickers as Dinah. After Fara lost 15 stickers to Dinah in a game, Dinah had 3 times as many stickers as Fara. How many stickers did Fara have at first?

Hi

What I am trying to show is usually used from P5, but I see no harm in introducing to P4 kids. I think it might be more efficient than MD for some questions.

For the second question, picture this.

Fara lost 15 stickers to Dinah. The transfer is between Fara and Dinah, hence the total number of stickers Fara and Dinah had still remained the same.

At first
Farah ----- 2 units ----- 8 units
Dinah ----- 3 units ----- 12 units
Total ----- 5 units ------ 20 units

In the end
Farah ----- 1 unit ------ 5 units
Dinah ----- 3 units ------15 units
Total ----- 4 units ------ 20 units

Use equivalent ratios. Make the total number of units the same. A common multiple of 4 and 5 is 20

Now compare Fara’s units before and after.

8-5 ----- 3
3 units ------ 15

1 unit ------ 5

Fara ----- 8 units -------40.

Best wishes

[chloecube]

Thks Tianzhu, you always make tough questions appear simpler after the explaination

[chloecube]

Hi

here is another question that i am stuck…

Tom had 1/4 as many red pens as blue pens. after he bought 5 red pens and 5 blue pens, he had 1/3 as many red pens as blue pens. how many red pens did he have at first?

[Singfrench]

chloecube:

Hi

here is another question that i am stuck...

Tom had 1/4 as many red pens as blue pens. after he bought 5 red pens and 5 blue pens, he had 1/3 as many red pens as blue pens. how many red pens did he have at first?

Before
red 1 unit
blue 4 units

After
red (1 unit +5)
blue 4 units +5 = [(1unit+5) + (1unit+5) + (1unit+5)]

hence 4 units+5 = 3 units +15
so 1unit = 10 red pens

drawing models would be clearer..

[chloecube]

Tks singfrench

[chloecube]

Hito and Tom had the same number of stickers. After Hito lost 3/5 of his stickers and Tom 8 more stickers.Tom had 3 times as many stickers as Hito. how many stickers did each of them have at first?


after working out with MD, the answer i got is 40

can someone advise if i am correct?

Thks

[MathIzzzFun]

chloecube:

Hito and Tom had the same number of stickers. After Hito lost 3/5 of his stickers and Tom 8 more stickers.Tom had 3 times as many stickers as Hito. how many stickers did each of them have at first?


after working out with MD, the answer i got is 40

can someone advise if i am correct?

Thks

bingo!

cheers.

[chloecube]

MathIzzzFun:

chloecube:

Hito and Tom had the same number of stickers. After Hito lost 3/5 of his stickers and Tom 8 more stickers.Tom had 3 times as many stickers as Hito. how many stickers did each of them have at first?


after working out with MD, the answer i got is 40

can someone advise if i am correct?

Thks

bingo!

cheers.

thks!