Calculate and Learn about Percentages with Percentage Calculator
Wesley Fryer, Moving at the Speed of Creativity, January 27, 2012.

Honestly, you shouldn't need a calculator to be able to figure out percentages. It's easy. I'll show you how, where a small number (say 13365) is a percentage of a big number (say 456312):
- Divide your big number by 100. Eg. if it's 456312 you now have 4563.
- How many times does that go into your small number? Eg., how many times does 4563 go into 13365?
- If that's too difficult, divide each number by 10 and round off until it becomes simple. How many times does 456 go into 1336? Still too hard? How many times does 46 go into 137? Still too hard? How many times does 5 go into 14? Just under 2.5.
- Sure, it's a bit ballpark, because of the rounding (the actual percent in the example is 2.93 percent, which is actually near the outer edge of the margin of error for this method). But you can do it in about 5 seconds in your head.
- if you need more precision, proceed stepwise, calculating 1 significant digit each time you divide by 10, and keeping the remainer for the next step. Like so: 4563 goes into 13365 2 times; 456 goes into the remainder (4339) 9 times, etc., giving you 2.9
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Re: Calculate and Learn about Percentages with Percentage Calculator

Anymouse, January 29, 2012

Hey. Right now, I'm starting a site for my high school club (it's in my URL). Basically, what we're trying to do is to create a one stop shop for information regarding high school teenage life. I came up with this idea because (I don't have an older sibling) I wanted to help others who had similar questions as me, such as "where can I volunteer" or "what courses should I take in Gr. 11".
So basically, I'm trying to get the word out about this site on the web. Could you please help me, such as maybe linking to our site in on of your posts? If you could, thanks a bunch. :) If not, that's ok too. I understand. [Comment] [Permalink] [Previous][Next]

Re: Calculate and Learn about Percentages with Percentage Calculator

Anymouse, January 31, 2012

Stephen,

I'm Matt, the creator of the tool reviewed in Wesley's post. Sure you shouldn't need a calculator to figure out percentages... and that's the reason I made the tool: to help kids learn to do it.

P.S. it would be nice if you could link to the site in question :) ( http://percentagecalculator.info ).

kind regards,
Mateusz Mucha [Comment] [Permalink] [Previous][Next]

Re: Calculate and Learn about Percentages with Percentage Calculator

Stephen Downes, January 31, 2012

But it doesn't teach kids how to do it, it just gives them the answer. A better tool would offer some indication of *how* it arrived at the answer, perhaps by providing a graphical element that will enable kids to make off-the-cuff calculations themselves.
[Comment] [Permalink] [Previous][Next]

Re: Calculate and Learn about Percentages with Percentage Calculator

Anymouse, January 31, 2012

You're right, I need to think of something that would show the process (and maybe visualize how numbers relate to each other... a pie chart perhaps). [Comment] [Permalink] [Previous][Next]

Re: Calculate and Learn about Percentages with Percentage Calculator

Stephen Downes, January 31, 2012

Well, I don't think a pie chart will be very useful for percentages greater than 100% and also for very small percentages like 0.06 percent [Comment] [Permalink] [Previous][Next]

Re: Calculate and Learn about Percentages with Percentage Calculator

Anymouse, January 31, 2012

Got a better idea how to show a relative size of two numbers that are so far apart? (sorry, English is not my mother tongue) [Comment] [Permalink] [Previous][Next]

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