basic math help and a few science questions about how on going about to study for it (1 Viewer)

Riot09

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1.this is a personal question-why do you get different answers if you either divide or answer or use a fraction in a calculator?

such as v=pi*r^2*h (for example)

905=pi*r^2*18
905/pi*18=r^2

square root 905/18*18=r (so if in this part i express it as a fraction i get 16 and squre root it to equal 4 which are both answers out of the ones to choose from the "answer pool".pretty much i do it separetly the same thing goes for when im doing the compound interest and depreciation formual i always do the brackets first then squre it and finally times that buy the principle to get the answer.is this happening becaus of my calculator is it just a normal?.


also how do i do thises one without a calculator to get the following answer

a). 396 divided by 110=3.6

b). 250x80 divided by or as a faction by/to 32 = 625

c).72x(1000/3600)=20 (how d i divide 1000 by 3600 mentally without a
calculator,just that part would be fine thank you).

d). 1000 divided by 28 times pi=1136.8

2.i read somewhere that the science school certificate test is half knowledge based and the other skills based is this true or a just a rough estimate or does it generally lean toward a "side". because the scince sc mc is really and when we were doing the 2008 practice paper in class a few weeks ago me and my friend finished that section in like 15-30m,most the time we were just looking at the question and saying out the answer out loud to see who got it first or if it was a bit tricky we worked together on it.

3.and if i got most of the mc on lockdown do you suggest that i solely work on the non-mc questions,half-half or 40% mc and 60% in terms of revision effort/time.


4.and finally should i read everything from year 9 and 10 science,just read my year 9-10 handbook which just a summary of those years,or go over my notes which is pretty comprehensive its like 40 pages long.

5.what do you suggest/recommend i do? or do you have another method to go about studying for this subject.

that would be all,thank you.:balloon:

(i really love this site i cant believe i just found out about it just recently the community is really friendly,helfull and non-judgemental unlike some of the teachers at our school.anyway i thanks for all the help i really wouldn't like to know if i didn't discover this site a few weeks ago.flying blind would be my first guess.
 

supre

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Re: basic math help and a few science questions about how on going about to study for

also how do i do thises one without a calculator to get the following answer

a). 396 divided by 110=3.6

b). 250x80 divided by or as a faction by/to 32 = 625

c).72x(1000/3600)=20 (how d i divide 1000 by 3600 mentally without a
calculator,just that part would be fine thank you).

d). 1000 divided by 28 times pi=1136.8
from which SC paper did u get these questions out of because as far as i know, they don't put in stuff too dramatic in SC as everyone from unintellectual people to brainiacs sit the same exam. and all the non-calculator sections of SC i have looked at until now dont ask for this kind of working for a question...
 

silence--

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Re: basic math help and a few science questions about how on going about to study for

a) 110 = 11x10 --> 396/110 = (396/11)/10 = 36/10 = 3.6

b) 250x80/32 --> simplify it first (divide top and bottom by 16) = 250.5/2 = 1250/2 = 625

c) 72(1000/3600) --> do it one step at a time, 72x1000 = 72000, then divide by 3600 = 20

d) ...? is this (1000/28) x pi or 1000/(28pi), either way you don't get that answer or i misunderstood the question :/
 
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Riot09

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Re: basic math help and a few science questions about how on going about to study for

from which SC paper did u get these questions out of because as far as i know, they don't put in stuff too dramatic in SC as everyone from unintellectual people to brainiacs sit the same exam. and all the non-calculator sections of SC i have looked at until now dont ask for this kind of working for a question...
its from a sc maths book i bought its got like 6 different tests created by sc math markers and teachers.so its just practice .
 

Riot09

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Re: basic math help and a few science questions about how on going about to study for

thanks guys
 

DInfinity

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Re: basic math help and a few science questions about how on going about to study for

If you only need a rough estimate, then I suggest substituting pi with 22/7. I find it makes calculating much easier in fractions than in decimals, but keep in mind it's only correct to the third decimal.
 

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