Q&A - P4 Math

[cftan]

HAPPYH:

BigDevil:

With DD in P4, I'm also interested to find out how to do this \"estimation\".

Just by visually, or have to work out the problem?

In the question posted by cftan,
384 x 23 = 8832
380 x 20 = 7600
400 x 20 = 8000

So the better estimate is 400 x 20 (difference of 832 from actual answer,
as compared to difference of 1232 for 380 x 20).

My goodness. I always tell my DD rounding of to the nearest 10 will be the better estimate. Unless they do proper multiplication, they will not know the correct answer. Really this estimation confusing.

Hi,

I had checked with DS's teacher and was told that the students are not expected to derived an actual answer before they select the correct answer for MCQ. It is a question on estimation. So got to just \"Estimate\" and not \"calculate\". Unless the child is very good is mental calculation else all the workings to derived to an actual answer might takes up too much time.
Just to share the feedback that I got.

[BigDevil]

Did the teacher provide guidelines on how to estimate?

[BigDevil]

Poppet:

A figure has a total of 324 squares.Which figure is that?


Can someone solve this question? :?:

18 x 18 = 324

[Poppet]

Ron and Sharon had the same amount of money.After Ron gave $81 to Sharon, she had thrice as much as Ron.How much more money did Sharon have than Ron in the end?



Can anyone help solve this question?

[iLoveChubby]

Hi Poppet

The only possibility that S can get thrice the amt of R after R gave S $81, is that R is giving S half of what he had.

So after R gave S $81,
R (left) = $81
S (now) = $243 (3x$81)
Difference = $162?

Or a faster way is after establishing e fact that R gave S half of what he had,
R = 1 unit ($81)
S = 3 units
Difference = 2 units = $162

[plum-cake]

Hi,

I need help Please…
Tin Jin saved $3500 in April. His monthly salary is twice the amount he saved in April. He saved $4200 less than the amount he spent in May. How much did he save in May?

from MPH P4 math work book, Part 1 page 53.

TIA

[ponyo]

monthly salary=3500*2=7000

Assume no change in salary,
then in May, amt spent+amt saved=7000

http://i48.tinypic.com/3588e2b.jpg\">


2u->7000-4200=2800
1u->1400

Amt saved in May =1400

[Poppet]

Look at the sum below.

72 divide by 6=12
How would you use this to find the answer to:
7200 divide by 6=_____

Can anyone help to solve this question?

[plum-cake]

Thanks Ponyo, I got it…

[kgaihc]

I have a way to solve the following question, but too long-winded. I believe there should a better method. Can someone help? Thanks.


Ali had four times as many storybooks as Gopal. Maggie had 336 fewer storybooks than Ali. The three children had 780 storybooks. How many storybooks did the two boys have altogether?