Wrote this educational fractions-calculator, because my kids were doing fractions. Also available in Dutch. I know it’s not bug free yet, but feel free to post errors it makes or things you feel it could explain differently/better.
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8 comments to Fractions-calculator |
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Can you better explain your kids why there is an error when dividing by zero and only by zero?
You get an error not because there’s an infinite number of possible answers, nor because the answer is infinitely long. You get an error because of the way that division is defined.
The most elegant summary of the problem is given by Ted Chiang, http://www.fantasticmetropolis.com/i/division/ :
“Dividing a number by zero doesn’t produce an infinitely large number as an answer. The reason is that division is defined as the inverse of multiplication; if you divide by zero, and then multiply by zero, you should regain the number you started with. However, multiplying infinity by zero produces only zero, not any other number. There is nothing which can be multiplied by zero to produce a nonzero result; therefore, the result of a division by zero is literally “undefined.””
Karin quoted Ted, saying: “There is nothing which can be multiplied by zero to produce a nonzero result” Let’s put that same statement in numbers: “There is 0 which can be multiplied by 0 to produce a nonzero result.” So Zero times Zero must be something positive after all! I bet I could create a scientific religion around that funny number Zero. Something along the lines of “God is Love”, (and we all know “Love” means “nothing” in tennis). So God is Zero. Which explains his absence. There you have it!
And theres a small error that could lead to xss (which can be really nasty in combination with wordpress.. same server: same hostname). Filter your double quotes
. Try “>.
But the whole seems fun, good job! Can you also build one to help me solve difficult integrals ;p.
(You helped me visiting blackhat day by arrayseminars, about a year ago.)
In the dutch version you have a small typo: ” … hierboven dan geef[b]t[/b] ik het antwoord … “
Beste Rop,
Mijn studio ‘Sandberg Instituut’ zoekt contact met je voor evt een lezing te geven. Ik heb Ank haar email in deze comment gestopt. Anders bel: T(+) 31(0)20-5882404 en vraag naar Ank.
Hopelijk kan je op deze manier in contact komen.
Met vriendelijke groet,
Ruben van Leer
mooie calculator Rop, ik ga ‘m zeker aan zoon Arthur laten zien morgen!
Heya,
if you are not adverse to teaching your kids some ‘unconventional’ math, then I suggest you look into ‘Vedic Math’.
If you want I can look up the name of the book, or bring it by.
As an ‘uncle’ with a penchant for ‘things sciency’ I taught a couple of kids Vedic Math (they are between 7 and 11).
The fun thing is, they now can do any arbitrary grade-school calculation faster than you can type them in into an electronical device.
The big trick is to translate the Sutra’s (rhyme’s that hold the algorithm’s) into dutch. And then playfully do a couple of excercises.
I got scolded by one school for teaching them ‘alternative ways’ in math. This ended up by me giving a lecture to the director of the school, explaining that I did not want ‘my kids’ to be ‘fodder for the consumer society’.
In the end though, they are not allowed to use that math, even though it is way simpler, but they still use it to do the calculations by heart, then work towards the answer in the traditional ways.