Cool math hacks

[Freyaday]

Xeda and Zippy have the coolest math hack of all: Their math is in color!

[ruler501]

So is the only real difference that you carry backwards(from the original method)?

EDIT:what are their math hacks Freyaday?

[Xeda112358]

Yeah, but you get your numbers in the order you say them or write them, too. You just have to know the next number making it easier to store in your memory

[ruler501]

ah. I might try using that sometime. I like things that make the maths easier.

[PeonHero]

but then you have to carry backwrds

  186
+145
-------

How would you solve that easier than the regular method

Dang, I did this in like 2 seconds, too fun.

  186
+145
-------

First you do the left column first: 100+100 = 200
Next column: 40+80 = 120
Add that to the last number we got (200+120) = 320
Last column 6+5 = 11
Add that to the last number we got (320+11) = 331

[Ashbad]

actually, I agree with that method

 5682
+ 970
-----

5 +15 carry 1 so 6, 5 +15 carry one 66, 5+ 2, 6652.

AND, I beat my time doing it this way than by pulling up a calculator.

[Xeda112358]

I usually start with the second digit to obtain the carry over for the first. So I do:
8+4=12, I get the carry of 1
Add 1+1+1=3
Then I go to the last numbers 6+5=11 meaning a carry of 1 to add to the 2 from before and I get 331

It takes me three quick steps to do that as opposed to 6+5=11, carry the 1 to get 8+4+1 and now I have 13 meaning you have a carry and the first two digits are 31, then you add the carry +1+1 and you get 331. It is too cluttered for me to think that way

EDIT:

AND, I beat my time doing it this way than by pulling up a calculator.

Hehe, nice! I love being able to do that because that further affirms the notion that my calculator isn't meant for basic math

Also, I find that the best times to learn fast techniques is through math games I made one that I actually find to be fun and it lets me practice my math operations ^^ I want to add timing to it, too (As in, timing a 10 question quiz on 3 digit multiplications ) It keeps a running score of the number of correct and incorrect questions in each category
EDIT2: It also will not accept any non-number characters

[ruler501]

So no hex work on that then Zeda. I don't time myself much and I try not to do that much of the more computation extensive math. I prrefer working on more complicated things instead of the basics. even if working on the basics would mean pretty good speed

[Xeda112358]

Hmm, well it really is beneficial to know all the ins and outs of how numbers act and react to each other. It really does help in advanced math. Like, take for example when I found a method of finding an equation for any finite set of data-- that is because my brain was in one of those moods where it was randomly spewing off all of my knowledge of numbers until it hit a connection. This only happened because I was having fun playing with simple addition and subtraction!

[Deep Thought]

I've just seen the E looking thing before and idk what it's called

It's summation, and it's called the sideways M sigma notation

* Deep Thought not understand first post either

[Xeda112358]

Yeah, I cannot think of the name of the symbol (the letter)... is it sigma?

[Freyaday]

Yeah, It's sigma

[DrDnar]

Σ is sigma, for sum. (Sigma makes an S sound, not an E sound. So "GRΣΣK" is very, very wrong.) Similarly, Π is pi, for product. And μ (as in μm, micrometers) is mu, for micro.

I do mental addition from left to right, my justification being that it's better to start with an estimate and then refine your estimate than deal with digits that probably don't matter when you're doing mental math.

[Munchor]

This is a Maths hack. However, it was taught in Physics (and it's related to Physics).

My teacher gave us this formula:



The result is always positive. However, it is sometimes negative, but due to the modulus operator we have to know when it is positive or negative by looking at the context and values.

I thought this was stupid and came up with this:

W = Qf - Qq

This gives us positive or negative values when positive or negative and works just fine.

To calculator efficiency we just have to do:

n = (|W|)/Qq

n is efficiency.

[ruler501]

What is that formula for?

and why does your method work. They don't look like they would give the same result.