/sci/ - Science & Math

>>7114387

A = 1, B = 9, C = 0

>>7114434
As I suspected my premise was the fault. Fucking welp. This is ridiculous though. How am I supposed to arrive at Calculus at this rate. Can't even solve these problems.

>>7114442
I actually didn't read any of the other stuff.
Here's how I solved it:


1. I know that A, B, and C are all single digits. Adding two digits gives either a one-digit number, or a two-digit number with 1 in the ten's place.
2. Therefore, A has to be 1.
3. Then, A+B (or A+B+1, if something was carried over) has to be a two-digit number, which means 1+B (or 2+B) has to be a two-digit number. Only two possible cases: B = 9 or B = 8.
4. Plug in B = 8; it doesn't work, because you get 9s in the bottom, and we already know A must be 1. Therefore B = 9.
5. Then, A+B has C in the one's place. We know A=1 and B=9, so C=0.

>>7114449
the first deduction is so well analyzed
;_;

>i'll never be analyze as good as this

>>7114449
>1. I know that A, B, and C are all single digits. Adding two digits gives either a one-digit number, or a two-digit number with 1 in the ten's place.
>2. Therefore, A has to be 1.
>>7114455

I did not even see it like this ;_;
fml

>>7114455

>>7114387
>>find books to brush up on my math to later tackle calculus
>calculus

Uhh, you don't need this stuff for calculus.

>>7114442
go to khan academy and start over. elementary math, it should take you about a week to arrive at HS math then that could take you a bit more and so on, but in a month you could refreshe all of the knowledge of mathematics you have

>>7114387
>Struggling with grade school algebra

You should see a doctor about your brain tumor and find out how much time is left.

>>7114473
thank you for your contribution.

>>7114387
OP, you don't need this stuff in order to learn calculus, they are unrelated.

Such a basic question man and I didn't even answer it

>>7114477

I know people that don't understand a single thing about calculus, about what calculus is, what it does and why it does, but yet they just practise and follow those simple instructions and get good grades. So OP if you are just about the grade don't worry too much about understanding it.

>>7114464
>>7114477
But MIT told me differently

>http://ocw.mit.edu/courses/intro-programming/
>6.00SC Introduction to Computer Science and Programming
Prerequisites: [..] You should be confident with your math skills up to pre-calculus.

>>7114466
thanks kindred anon. i have a few months left in my disposal.

>>7114442
>This is ridiculous though

A*111+B*111=A*1110+C
A*111+B*111=A*1110+C
B*111=A*(999)+C
B=A*9+C/111

since A,B,C<10 and 111 divides C, C=0

A=9*B

only B=0 and B=1 keeps A<10 so A=B=C=0 which is retarded or A=9, B=1, C=0

>>7114482
Oh no, I'm not after the grades. I'm tackling the prerequisites needed for this program >>7114484

I have a few months left to decide which major I should choose for college. I'm really undecided so I'm trying to take the online MIT course to find what CS is like.

>>7114477
>OP, you don't need this stuff in order to learn calculus, they are unrelated.

>Algebra, Arithmetic, Logical Reasoning
>unrelated

Yeah, no.

>>7114492

Can you please tell me where you took a calculus course that required you to solve cryptarithms?

>>7114484
>Computer Science

I am so sorry.

>>7114494
>cryptarithms
>straight forward word problem in algebra

7.5/10 if trolling
>>>/out/ if serious

>>7114500
Yes, I know it is straightforward. You still haven't answered the question.

Once again:
Can you please tell me where you took a calculus course that required you to solve cryptarithms?

>>7114487
>>7114487
>A*111+B*111=A*1110+C
>A*111+B*111=A*1110+C
>B*111=A*(999)+C
>B=A*9+C/111
>since A,B,C<10 and 111 divides C, C=0
>A=9*B

wakarimasen

>tfw I've actually thought of going for stats last year.

Thank god my college life still didn't happen. What the fuck was I thinking. I mean I like maths but I've been out of school for so long that I'm out of touch with things. I even lost my blazing quick mental calculation.

I've gone from CS to CE to Stats to nothing at all. Fml.


>>7114496
nice meme sir

>>7114502
>that required you

Right here

>cryptarithms

The name you're looking for is "word problems".

>>7114503
>wakarimasen

おめえは馬鹿だろ。 これ以上簡単な問題があらねえぞ…

>>7114387
>>doesn't describe its aims,

Algebra, nah that's would be crazy....

>methodologies

Mathematics with more mathematics

>>7114449
How did you arrive at the conclusion that A is equal to 1?

>>7114523
A<10
B<10
A+B<20

>>7114523
>or a two-digit number with 1 in the ten's place

>>7114526
>>7114527
7 is a single digit, you can add 7 and 7 and get 14. That's a two digit dumber with 1 in the ten's place.

>>7114530
did you even look at the problem?

>>7114466
Btw, I should mention that I've tried Khan Academy already last year. It was alright but the testing system can be flawed at times. Sal too. It's also a pita to watch the long videos on top of a shitty connection.

I feel like I'd rather have textbooks this year than videos, so recommendations in that are highly appreciated.


>>7114517
>馬鹿
>あらねえ
アホはお前だろう。数学に個室しろ。

>>7114521
Not Algebra's aims, but the aims of the book. It doesn't even open up what it's going to equip you, if the book is comprehensive or not, whom the book is for or whatever. It's poor in that aspect. Seriously, they just pasted Algebra in the title and jumped in immediately to the problems and topics. No preface, foreword, no anything.

>>7114536
Yes, and I'm having trouble seeing why it's specifically 1. Why can't it be 7? Or 6?

>>7114542
>>馬鹿
>>あらねえ
>アホはお前だろう。数学に個室しろ。
Okay, we're even 固執.

>>7114542

>>7114543
see >>7114526
the A in the thousands digit can only be 1

>>7114548
>the A in the thousands digit can only be 1
Why? And why does this make A=1.

>>7114550
you cannot be this stupid surely?

>>7114551
Explain it to me instead of being a douche.

I'm looking at

AAA
BBB
AAAC

Why is A=1 only and why does that last A have to be a 1?

>>7114543
7+{0-9}+{0-1}=77

>>7114555
Well then why is B=9 and C=0?

>>7114555
Where the fuck you get subtraction from?

>>7114556
1+{0-9}+{0-1}=11
B=9

111+999=1110
C=0

>>7114557
7+ (0 thru 9) + (0 thru 1)=77

>>7114558
I am so fucking confused.

>>7114546
Yeah, I get what the book is trying to do but still. The criticism in the first review has some truth for Khan Academy as well.

Well, I guess I just have to carry on? It sucks though. I've already difficulties at the very start of the book when

>The book is divided into sections devoted to different topics. Some of them are very short, others are rather long.
Of course, you know arithmetic pretty well. However, we shall go
through it once more, starting with easy things.
>easy things

But, it's not like there are other ways but to move on forward. I don't know how it will equip me though if I get stumped with every problems and the only problem to solve is the one you already know the solution of. It's like, fail every problems and this book and somehow you've learned Algebra.

>>7114558
How did you figure this out?

Like I'm rereading his proof.

> I know that A, B, and C are all single digits. Adding two digits gives either a one-digit number, or a two-digit number with 1 in the ten's place.
This makes sense. Obviously none of them are above single digits.

But then.

> Therefore, A has to be 1.
???????????????

>>7114553
you don't have enough from the sum in the hundreds column for the A in the thousands column to be more than 1

>>7114553
if both A and B are 9, you still get 999+999 = 1998
thus A cannot be over 1 because there are no sum of two three-digit numbers that are greater or equal to 2000

if A is 1 then the problem is simply 111C - 111 = BBB
since BBB is a three-digit number 111C - 111 has to be less than 1000 and thus C can only be 0 which makes B = 9

>>7114563
But if A was seven you can still add that and get a number with 1 in the thousandths column.

>>7114565
what the fuck did you just say

I am not bad at math I am a sophomore doing my ODEs and having an easy timE BUT WHAT THE FUCK IS THIS SHIT

>>7114560
{A=1}+{B=0,1,...,9}+{carry=0,1}={AA=11}

>>7114562

0AAA+
0BBB=
AAAC

=>

0A+
0B+
0carry=
AA

0≦A≦9
0≦B≦9
0≦carry≦1
0≦A+B+carry≦19

AA can only be 00 or 11.

>>7114568
could you explain it without all the notation it is confusinG ME

>>7114566
>But if A was seven you can still add that and get a number with 1 in the thousandths column.

That thousandths column is A too. You can't have A=7 and A=1

>>7114387
Wait, I don't get it. Where in the image does it say the sum has to be 1000? If I needed five numbers, with eights in the ones digit, to equal a number with zero in the ones digit, why can't I just say 8+8+8+8+8=40?

>>7114566
You're clearly being obtuse on purpose, you don't even want to understand

Just look at the problem jesus fuck, you're even saying you understand that you can only get a 1 in the thousands column and the A is right there holy shit

>>7114568
Don't you mean less than/equal to 18?

>>7114553 ok so first thing, a+b carries over 1 because the sum of 2 digits can carry over 1 max, and now you look at the second and first sum, c plus the carry over equals c, a+1=c. Now you look at the last sum a+b carries over 1 and so the last digit should be a 1, a=1 and c = a-1=0.(first sum) 1+b =1c (1c is a two digit number), 1+ b = 10 since c=0 which means b=9

>>7114571
That's another problem bro. Look at the page and headings. It's different. You're solving problem 2 not #1. The answer is 1110.

>>7114573
9+9+1=19

>>7114570
no thats not what I mean I mean A=7 and thats it all As equal 7 WHY IS THIS SO HARD FOR ME WHAT THE FUCK

>>7114572
No, I said I understand why if you add A+B or whatever, you get a 2 digit number with 1 in the ten's place.

Why does the thousand's place A have to be 1 tho?

>>7114566
>I am not bad at math
your demonstrating otherwise mate lol.

>>7114572
Even so, if the thousands A is 1, why does that mean A=1?

>>7114574 c plus the carry over equals a, a=c+1*

>>7114574
>a+1=c
so 1+1=0?

>>7114582
>Even so, if the thousands A is 1, why does that mean A=1?
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

>>7114579
777+y=7770+C
y=6993+C
but C>0 and y<1000

doesn't fucking work

>>7114579
>if you add A+B or whatever, you get a 2 digit number with 1 in the ten's place
>you get a 2 digit number with 1 in the ten's place
>1 in the ten's place

>Why does the thousand's place A have to be 1 tho?

Relax a bit, you're literally writing the reason A can't be anything but 1, over and over again
Soon, soon

Try making the problem smaller, only use 1 digit
A + B = AC

>>7114574
this is fucking gibberish

>>7114585 i have corrected it

>>>/g/tfo

>>7114586
Listen man.

If A=7.
And B was 5.

A+B=12
plus the carry
13

So the thousands place is still 1 even tho A=1.

>>7114577
Oh, thanks.

>>7114542
you could torrent khan academy and then watch it later, and for the long videos you could speed it up to 2x the speed, it works great

>>7114593
no dipshit, A is forced to be 1 by the argument thats been presented to you five or six times now.

>>7114593 all the a's are the same digit so all a's have to be 1

>>7114588
OH, so the A in the addition up there is the SAME as the A on the bottom?

OKAY THATS WHAT WAS FUCKING ME UP I GET IT NOW

>>7114598
>>7114599

Congratulations, this is the key to algebra. All x's are the same, all y's are the same, all A's are the same, etc

I FINALLY UNDERSTAND

SINCE WITH SINGLE DIGIT NUMBERS ADDED TOGETHER, MAX YOU CAN GET IS A TWO DIGIT WITH 1 IN THE TENS PLACE

AND SINCE THE A'S ARE ALL THE SAME AND NOT DIFFERENT

IF A+B=AC

THAT MEANS A HAS TO BE ONE SINCE WE GET A TWO DIGIT NUMBER

HOLY shit I am so HAPPY I LOVE MATH

>>7114599
>symbols mean the same thing throughout the entire equation
It happens a lot really

>>7114599
kill yourself

>>7114603
This feeling is the best, math is addictive as fuck

Could A+B=AC be satisfied with A=1, B=17, C=8?

>>7114609
They say a b and c are digits so b cant be 17

>>7114611
I'm breaking off from the problem in the OP.

This is new.

A+B=AC

A HAS to be 1 since the two digit you're getting is ending in the same thing as up there.

But nothing is keeping B from being more than 1 digit. But it HAS to be two digits.

So if B is 17, 1+17=18.

This satisfies AC, since A is the same, and C is a different number.

Am I wrong?

>>7114595
>and for the long videos you could speed it up to 2x the speed,
I did that in the YT player itself, indeed it's incredible but I've spent months with Sal already last year. It kinda gets tiring. I have enough of Sal. And like I said the testing system can be flawed. There are some obvious automated things there acting as hints that render the exercises useless. I feel like the format has an exploit and it doesn't really make you learn. Of course, there's also that I could be using it wrong..

>>7114561
Well /sci/. Hope this recommended book from the wiki will really make me learn Algebra ;_;

>>7114615
B can be any one of 9, 11, 12, 13, 14, 15, 16, 17, 18

>>7114615
Yes that is a solution then. There are others for 9+c=b

>>7114633
Does C have to be a positive integer?

>>7114635
I dont know the exact conditions to this problem but i assumed c had to be a digit so positive integer <10

>>7114639
how does that fucking work?

It would have to be a decimal.

9+.5=9.5, so C is different

>>7114641
What are you talking about ? Why does c have to be a decimal?

>>7114648
Because B is a single digit number obviously.

9+1=10, which is a two digit number. so it has to be less than 1.

>>7114660
The poster of this particular problem said b didnt have the restriction of being a digit

>>7114665
oh, well then that's easy

9+c=B
9+5=14
B=14

what is hard

>>7114667
Y its easy i was simply explaining the other solutiosns

Can someone explain me how the method of coordinates is on the grade schooler section? Has anyone read that? How on earth could the average grade schooler understand that by himself? That's absurd!

What you need to know before calculus is

1. graphing functions of all types without a calculator including: rational, binomial x^2, trinomial x^3, even/odd polynomials, as well as shifting functions, stretching functions, finding zeros

(this includes the standard form of a parabola)

2. basic algebra such as exponents
realize (x+y)^n is not (x^n + y^n) and,
x^-n = 1/(x^n)

3. polynomial expansion using pascal's triangle

4. synthetic division to find zeros and to divide out polynomials

5. quadratic formula

6. basic trigonometry, such as the unit circle, and how the hypotenuse can be "projected" onto the sin/cosine axis

I tutor Calculus students.

>>7114717
>1. graphing functions of all types without a calculator including: rational, binomial x^2, trinomial x^3, even/odd polynomials, as well as shifting functions, stretching functions, finding zeros
I agree with this.
>(this includes the standard form of a parabola)
>2. basic algebra such as exponents
>realize (x+y)^n is not (x^n + y^n) and,
>x^-n = 1/(x^n)
I agree as well.
>3. polynomial expansion using pascal's triangle
Yes.
>4. synthetic division to find zeros and to divide out polynomials
I prefer long division, which works the exact same.
>5. quadratic formula
Yes, but who doesn't know this?
>6. basic trigonometry, such as the unit circle, and how the hypotenuse can be "projected" onto the sin/cosine axis

>memorizing the whole unit circle
bruh

>>7114733
>>memorizing the whole unit circle

why would you memorize it if you understand it? wot? is this murica thing? math isn't history you know

I love this topic because it is how I felt a year ago when I finally "got" precalc and understood the allure of maths

That said gelfand algebra is fkn hard if you were retarded like me, axler precalc (and learning formal logic) did it for me so I recommend those

>>7114740
Oh, I thought you were implying people should memorize it.

Hard where?

AAA
BBB
AAAC

A,B,C,D e[0, 9]

|A+B = DC
|D+A+B = EA
|E+A+B = AA

|E+B = A0
|D+B = E0
|A+B = DC

|A = DC - B
|D = E0 - B
|E = A0 - B

|A = 1
|E = 1

|1 = 10 - B
|D = 10 - B
|A = DC - B

|B = 9
|D = 1
|1 = 1C - 9

|C = 0

Ans
|A = 1
|B = 9
|C = 0

>>7114751
where did D and E come from?

also you did it a stupid way

>>7114758
Yes, I did it a stupid way to show that even grade schooler could solve this problem. D is declared as A+B=DC and E is declared as D+A
+B=EA, becase there are always some digits in the tenth place (D and E can also be 0).

>>7114717
Thanks bro anons. ;_; You're about the two people in this thread who really chipped in for my worries.
Life is hard, full of surprises and hardship. I've been at a standstill 2/3rds of my youth. Hopefully we're all gonna make it brahs ;_; One step at a time away from the depressed neet days.

>>7114712

It's baby level coordinate geometry. Don't tell me you're afraid of the 4D cube example which they spend half the book explaining.

>>7115385
Of course that at my age it wouldn't be conceptually difficult, what I was saying is that the average grade schooler could not understand this.

>>7115444
Oh god please ignore me. I realized that what I had looked at was a book of the same title but different author.

>>7115444
The point of the book is to show kids they can do stuff with geometric objects without even needing to draw a picture of it by using coordinate. There would be no point of it unless they did an example where you can't just look at it in space.

Line: {(0), (1)}
Square: { (0,0), (1,0), (1,1), (0,1) }
Cube: { (0,0,0), (1,0,0), (1,1,0), (0,1,0), (0,1,1), (1,1,1), (1,0,1), (0,0,1) }
Hypercube/tesseract: { (0,0,0,0), (1,0,0,0), (1,1,0,0), (0,1,0,0), (0,1,1,0), (1,1,1,0), (1,0,1,0), (0,0,1,0), (0,0,1,1), (1,0,1,1), (1,1,1,1), (0,1,1,1), (0,1,0,1), (1,1,0,1), (1,0,0,1), (0,0,0,1) }

Same shit just piled higher and deeper.

>>7114717
>What you need to know before calculus is

>1. graphing functions of all types without a calculator including: rational, binomial x^2, trinomial x^3, even/odd polynomials, as well as shifting functions, stretching functions, finding zeros

Gelfand/Glagoleva/Shnol, Functions and graphs

>2. basic algebra such as exponents
>3. polynomial expansion using pascal's triangle
>4. synthetic division to find zeros and to divide out polynomials
>5. quadratic formula

Gelfand/Shen, Algebra

>6. basic trigonometry, such as the unit circle, and how the hypotenuse can be "projected" onto the sin/cosine axis

Gelfand/Saul, Trigonometry

I would throw in some coordinate geometry (aka analytic geometry) and maybe some linear algebra.

>>7114747
>>7114740

What's there to memorize besides cos(30°)=1/2 and sin(30°)=√3/2?

>>7116110
Thank you based anon~!