4 ms·

I bought the book a while back, and I still struggled with it. I have very low math skills. My pre algebra teacher was a joke, and everything building on that f

I bought the book a while back, and I still struggled with it. I have very low math skills. My pre algebra teacher was a joke, and everything building on that flew right over my head. I basically talked my counselor into letting me graduate even though I didn't pass basic math graduation requirements in college. So I'm a pretty clean slate, and this was quite difficult for me. I'm a pretty good developer, but telling the computer to do math for you based on looking up what it needs to do is much different from understanding the concepts myself which has been a real difficult thing for me. Kahn academy is the worst, like bringing back old terrible memories of repeating hellish math problems that I don't really get, but still want to move on out of boredom. Such it is.

j2kun 11y ago
I would love to hear your thoughts about something I'm working on. Care to shoot me an email? jkun2@uic.edu
kalid 11y ago
Thanks for the feedback! The book is more of a "top concepts I wish I knew" but not really a ground-up tutorial. For starting from a clean slate, you might like: http://betterexplained.com/static/articles/rethinking-arithmetic-a-visual-guide/ http://betterexplained.com/static/articles/rethinking-arithm... Once you can visualize the basic operations (add, subtract, multiply, divide), every new math operation becomes a lot easier (complex numbers = rotations, exponents = growth, combining them = orbiting a circle...).
- lstamour 11y ago
  When you say the opposite can be the multiplication of -2, did you actually mean the multiplication of -1? It's a bit unclear in the example whether the "loss of two" means 1 * -1 = -1 and therefore a relative loss of two, or 1 * -2 = -2 or a relative loss of 3. I always figured opposite meant inverting either the fraction so 2/1 becomes 1/2 or it meant multiplying by -1, effectively toggling the negative sign.
  - kalid 11y ago
    Whoops, might not have been clear enough. In more mathy terms: Multiplication by 2 means "1 (starting point) times 2 (scaling)" If we "do the opposite" we can take the inverse of the starting point or the scaling: -1 (additive inverse of starting point) times 2 = -2 or reverse the operation 1 (same starting point) * 1/2 (scaling inverse) = 1/2 Of course, we assume the scaling term is what's being inverted, but it's important to think about the meaning. There's a hidden parameter for these operations and sometimes making it explicit can be helpful. (I.e., euler's formula, e^ix, is better seen as 1.0 * e^ix. That is, you are starting at 1.0 then doing a rotation.)

j2kun 11y ago

I would love to hear your thoughts about something I'm working on. Care to shoot me an email? jkun2@uic.edu

kalid 11y ago

Thanks for the feedback! The book is more of a "top concepts I wish I knew" but not really a ground-up tutorial. For starting from a clean slate, you might like: http://betterexplained.com/static/articles/rethinking-arithmetic-a-visual-guide/ http://betterexplained.com/static/articles/rethinking-arithm... Once you can visualize the basic operations (add, subtract, multiply, divide), every new math operation becomes a lot easier (complex numbers = rotations, exponents = growth, combining them = orbiting a circle...).

lstamour 11y ago
When you say the opposite can be the multiplication of -2, did you actually mean the multiplication of -1? It's a bit unclear in the example whether the "loss of two" means 1 * -1 = -1 and therefore a relative loss of two, or 1 * -2 = -2 or a relative loss of 3. I always figured opposite meant inverting either the fraction so 2/1 becomes 1/2 or it meant multiplying by -1, effectively toggling the negative sign.
- kalid 11y ago
  Whoops, might not have been clear enough. In more mathy terms: Multiplication by 2 means "1 (starting point) times 2 (scaling)" If we "do the opposite" we can take the inverse of the starting point or the scaling: -1 (additive inverse of starting point) times 2 = -2 or reverse the operation 1 (same starting point) * 1/2 (scaling inverse) = 1/2 Of course, we assume the scaling term is what's being inverted, but it's important to think about the meaning. There's a hidden parameter for these operations and sometimes making it explicit can be helpful. (I.e., euler's formula, e^ix, is better seen as 1.0 * e^ix. That is, you are starting at 1.0 then doing a rotation.)