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Nice title, eh? Let me preface this with the admission that I know just about nothing about dyslexia. Clinically, I mean.
The reason for this post is that Angela (Mother Crone) left a very interesting comment on yesterday’s post concerning how mental math has helped her daughter, who is dyslexic.
How many screwbulbs does it take to light in a dyslexic?
(Yes, that was unbelievably cheap.) Although I have no insights into clinical dyslexia, I have fought my whole life against certain dyslexic-like symptoms. I also suspect that any person who is at least mildly aware of his or her thought-processes struggles with similar symptoms.
Continue reading Mental Math and Dyslexia →
“In mathematics the art of proposing a question must be held of higher value than solving it.”
Georg Cantor
About a month ago, Penny commented on this post.
Here is an except from that comment:
“Frankly, I don’t care if an elementary school child can add long columns of numbers in their head – it is an almost worthless skill. I do care if they can think about mathematical concepts.
Better to teach them to come up with simple proofs (not memorized proofs) of basic facts in math.
Better that they should understand what a prime number is, and why we care about prime numbers.
Better that they should learn to enjoy slow, deep thought about puzzles and concepts.
That is where the gold standard in math education is.”
I wanted to revisit this thought, because Penny brought up some great points. I don’t disagree with any of them. But I must say that I, as well as a lot of the readers are coming from a different place. Penny is a brilliant research mathematician. A lot of us, on the other hand, basically have a history of thinking that we sucked at math (at least until we came upon Math Mojo, and learned that almost no one sucks at math, but some sometimes the way math is taught sucks.)
I wanted to address some of the points Penny made, because those points made me think a lot this month. Here’s
Continue reading The Value of Quick Addition Skills →
To check multiplication of single digits by longer numbers with playing cards:
We’re going to use what I call “numbers crunching” to check. That is the same as using the nines-remainders. You do know how to get the nines-remainder of a number, don’t you? It’s very simple, but it takes a bit of explaining.
It also pays to know why checking with nines-remainders works. Both of those things are beyond the scope of this article, but I’m working on a booklet and a video about how to check your answers for all of the basic operations of math using “number crunching”. There are lots of tips and shortcuts that make this method absolutely simple and effective. Let me know if you’re interested by using the “Contact” box near the upper right hand corner of this page.
(This video will be re-edited and uploaded by the end of Wednesday, April 30)
If you know about crunching, you’ll be interested to know that practicing with cards like this is perfect for checking with crunching. It turns out that if you crunch all the digits from zero to nine, you get a crunch number of 0.
Continue reading Practicing and Checking Multiplication With Playing Cards (2) →
Math Mojo has got some surprises for you. New lessons on how to improve your basic math skills, and videos! Professor Homunculus is getting his Video Mojo workin’ to bring you some great new stuff.
The first set of videos will be about how to practice multiplication using playing cards. So grab a deck of cards and [...]
A few posts ago, I offered some tips about how to check large division problems without having to multiply huge divisors and quotients to get even huger dividends.
One of the drawbacks to using the “crunch” method, which I described, is that it is not 100% accurate.
Often, people who need to defend the status [...]
We’ve been talking about using factors to make long-division problems easier, sometimes being able to turn them into a manageable sequence of short-division problems, in which no paper and pencil (and certainly no calculators!) are needed.
Want to try another one? How about
962/52 ?
Well, they’re both even, so that’s going to [...]
In the last post we looked at the problem of 926/18, and we simplified it to 463/9, so we could make it a short division problem.
What if the problem had been 927/18?
Both numbers are not even this time, so it is not readily apparent if they have common factors.
If you know how to factor (if you [...]
(Is that title an oxymoron?)
Imagine you have to do this division:
926/18
How would you do it? Would you rewrite it with that funny division symbol (“division bracket,” or “right parenthesis followed by a vinculum over the dividend”)? Would you use a calculator? (Please say “no” to that!)
After you rewrote it, would you start by trying to figure out how many times 18 would go into 92? If you did, you would be doing it the way most people learned in school, and you would be wasting a lot of time and effort.
Continue reading Long Division Shortcut (Part 1) →
This post is a continuation of the other posts about the video on YouTube entitled “An Inconvenient Truth” with M.J McDermott (not to be confused with Al Gore’s film) which concerns the dismal state of American basic math education in public schools. You can view it here.
M.J. had two good premises, but her conclusion does not jibe. “Their methods suck.” (True.) “My method is better.” (True.) “Therefore mine is the one everyone should use.” (Nahhhhh.)
Why don’t you experiment a lot and discover what works best for you, and keep refining it? It can be so much more fun and rewarding to do that. Respect your mind, not the opinions and emotional responses that were put there by others in the past. Try this stuff out, then decide.
It’s important to mention that people who think it’s OK not to learn the basic arithmetical operations because “you can do it with a calculator” are just plain damn dumb. That’s like saying, “Hey, this ‘walking’ stuff sucks. It takes effort! Why do we need to learn to walk? That takes years! Let’s just give everyone a wheelchair!’
Continue reading More Truth, Less Inconvenience →
(If you use a little imagination you can guess the title of this article.)
This article concerns M.J. McDermott’s youTube video about the sad state of basic math education in America. You can visit the video here, or you can simply scroll down to the next entry here in the Math Mojo Chronicles, where it is embedded.
It seems like M.J. McDermott has unleashed a firestorm that need to be unleashed. She’s gotten almost 60,000 hits in one week on youTube for a video about math! Imagine that! Good work, M.J.!
I’ve commented on that video several times, mentioning that there is at least one much better algorithm than what is called the “standard.”
Not one of the hundreds of other people who commented on the video seems to be aware of this, which is strange, because most of the comments to M.J.s video were posted by obviously thoughtful people. And one man who is obviously a lot better at mathematics than I am even made a video-reply to M.J.s video – but still stuck in standard mode.
Here is a synopsis of my part of the discussion so far:
Continue reading go(1/4)+X →
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