Am i wrong and overlooking something or am i right?

[cursive thistle]

Whats the point of making the powers the same before adding and then reversiving that action if you can just solve the brackets first, add and then write in standard form? is there a difference or is it just a different method? (the image is the teachers working)

[tired flax]

1. Wait patiently for a helper to come along.
2. Once someone helps you, say thank you and close the thread with:

+close

3. Feel free to nominate the person for helper of the week in #helper-nominations
4. Do not ping the mods, unless someone is breaking the rules.
5. If you're happy with the help you got here, and the server overall, you can contribute financially as well:

[cursive thistle]

oke

[worthy maple]

Well its generally easier because it means you can add them, and makes it more simple to do mentally.

But you could also just break it down to (30000)+(6000)

and then you know what 36000 is equal to 3.6*10^4

But its more quick if your able to see for example something like (7.8 x 10^6)+(9.2 x 10^4)

then noticing the two difference meaning that the total will be 7.892*10^6

[cursive thistle]

ah

[cursive thistle]

but if i do it my way, which is NOT the way in the image, would i still get marks for working if i get the answer correct

i cant tell here since its a quiz that im doing with only a right or wrong answer

its not like in the exam how there are multiple marks awarded for different things

[worthy maple]

Unless it specifically states to do it a certain way if your working is valid (and not trial and error) then yes it should be ok

but its just an expectation

[cursive thistle]

hm

hope you can read sideways

[worthy maple]

?

[cursive thistle]

Here is a question following my method

[worthy maple]

I see

[cursive thistle]

And I got it correct by checking the mark scheme

Which is

this

[worthy maple]

Now for when it is multiplying I would say its far easier

to just use your knowledge of powers

[cursive thistle]

and for dividing too

since it follows the same principle

[cursive thistle]

but for addition and subtraction the teacher recomends this approach

[worthy maple]

Did you do it with a calculator?

[cursive thistle]

yes, which is permitted in the exam

[worthy maple]

If its allowed in examthe sure, depends on the model but you can even set the model to give the standard form answer

But if they expect you to work it out its far easier to be (0.61 x 10^5)*(6 x 10^5) = 3.66 x 10^10

[cursive thistle]

thats what i did, look at the end of the image i sent ya

[cursive thistle]

yeah i did exactly that but just added 36600000000 before simplifying into standard form which is what the question is asking for

so its correct, unless im missing something

[worthy maple]

These questions shouldnt be worth many marks in the first place

as they are a simple calculation

so it should be graded based on an answer

[cursive thistle]

yee!

[floral ocean]

Otherwise you can't add numbers without removing scientific notation.
Basically, two number in scientific notation can be added only when their exponents are the same.

[cursive thistle]

just solve the brackets first, then add, then do standard form. THATS MY METHOD YOU RANGER MAIN!

[floral ocean]

That isn't a good approach in general. What if the exponents are very large or small?

That's the whole point of scientific notation.

[worthy maple]

They are using a calculator and its not meant to be done by hand

[cursive thistle]

exactly

[cursive thistle]

well when it comes to calculating whats in each bracket

for example (6.1x10^4)

[floral ocean]

Why use a calculator for this, though?

[cursive thistle]

i just type 61 in the calculator and add 3 zeros and not 4 since there is a decimal place once

[cursive thistle]

because i can 😄

also it would be faster in the exam

correct me if im wrong

im getting ahead of myself

[worthy maple]

I know, but they also are getting questions which are multiplying the standard form. At that point its better to do it by splitting (if working w/o a calculator)but if they allow a calculator...

But I still think its better if you understand the principle and are able to employ it

incase there is a question like this but is more then 1 mark, because then they will be looking for understanding

but if the questions are just basic quick a,b,c,d I would do whats quicker

[cursive thistle]

this principle even works with subtracting and adding brackets

although

[cursive thistle]

im going to have to agree with this since they can be very small, but even then it would be the same to write them down wouldnt it?

thank you @worthy maple @floral ocean

[bold blaze]

@cursive thistle has given 1 rep to @floral ocean @worthy maple

[floral ocean]

Well, yes. But I'm pretty sure the point of this problem is to work with exponents.

[worthy maple]

Yes, but also keep in mind if there is a large difference between the two, make sure you are using the correct number of sig figs

[floral ocean]

The case where you have to use a calculator is when the exponents aren't integers.

That happens in chemistry quite often, of course.

[cursive thistle]

yee

[cursive thistle]

what do you mean by that

[worthy maple]

like 2^3.5, 2^(7/2)

[cursive thistle]

oh as in the calculator being a necessity?

[floral ocean]

Suppose we have a solution with pC(K+) = 2.35. What's the concentration of K+ ions in it?

[cursive thistle]

no idea

what does the pC mean

and does the number represent moles?

[floral ocean]

Well, by definition pX = -lg(X). So:
C(K+) = 10^(-pC(K+)) = 10^(-2.35) M
Here, of course, we need to use a calculator. We get C(K+) = 4.47*10^(-3) M.

[cursive thistle]

is that A level chemistry or something

im doing IGCSE i have no idea what that is

[floral ocean]

No. Just an elementary problem.

IGCSE? What's that?

[cursive thistle]

International GCSE

i homeschool my GCSE's so they are IGCSE's

[floral ocean]

Still don't know what GCSE is.

[worthy maple]

The english system

[cursive thistle]

are you in college

[worthy maple]

British

[cursive thistle]

oops yeah my bad for not specifying

[floral ocean]

Fourth year of university.

[floral ocean]

Oh, some kind of exam?

[cursive thistle]

WOW CONGRATULATIONS FOR MAKING IT SO FAR

[floral ocean]

Thanks! 😁

[cursive thistle]

my dad is going to study uni at home

[cursive thistle]

yeah its basically end of secondary school

and since you are talking about uni equations i have zero knowledge of how to answer them

[worthy maple]

Kind of like the ib (diploma course)

with different levels of certain subjects

and a different exam

[floral ocean]

Don't know what ib is, but I think I get it.

[cursive thistle]

not to mention when doing homeschooled GCSE's, your applications to college are alot more generous

[cursive thistle]

basically, im in year 11, wbu?

[worthy maple]

You graduate in year 13?

[floral ocean]

Year 4 of university, as I said.

[cursive thistle]

um, yeahh 💅

[cursive thistle]

which would mean

year 17 ish?

[floral ocean]

Uh, what?

[worthy maple]

I would assume last year of a bachelor's degree. But i wouldnt know

[floral ocean]

We only have 11 grades in school.

[worthy maple]

not 12?

[cursive thistle]

sorry let me rephrase

[floral ocean]

No.

[cursive thistle]

you did primary, secondary, 2 years of college and now on your 4th year of uni?

[floral ocean]

Wait, no.

We have two options:

1. 9 grades, then college.
2. 11 grades, then college or university.

[cursive thistle]

option 2 is me rn ig

[floral ocean]

Oh, I see.
Well, if you didn't graduate early, why go to college instead of university?

[cursive thistle]

thats not how it works here

[worthy maple]

they assumed year 11 wasnt enough for uni but 13 i think

[floral ocean]

Oh, you have 13? Quite a lot.

[worthy maple]

Its different systems

I assume the american one doesnt include more kindergarten years

while the british one does

(dont quote me on any of this)

[floral ocean]

I don't know how either works, to be honest 😅

[cursive thistle]

@floral ocean @worthy maple thanks for the help and clarification, i will close this now ig

oo

[bold blaze]

@cursive thistle has given 1 rep to @floral ocean @worthy maple

[wise fable]

The tickets system is disabled for this server. Enable it at: https://yagpdb.xyz/manage/624314920158232616/tickets/settings.

[cursive thistle]

+close