Monthly Archives: April 2009

What is Multiplication – part X

Posted on 2009/04/29 by Bert Speelpenning

Yesterday, in the supermarket, a customer dumped a whole basket full of power bars on the counter.  The checkout counter person started to scan them in, one by one.  After seeing about seven of them scanned, with a lot more … Continue reading →

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What is Multiplication – part IX

Posted on 2009/04/26 by Bert Speelpenning

In the diagram below, I have collected some of the examples introduced in the prior post in the series on multiplication.  Each example is presented in two ways: on top, as a box with an input and an output, and … Continue reading →

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Math in the Comics – part 10

Posted on 2009/04/26 by Bert Speelpenning

From last week’s Foxtrot comic, another take at the cultural background conversation of math. Who is bad at math? At one level, a puzzle.  The top part, the part that starts with “16-11-13-5” is not a subtraction problem.  It is … Continue reading →

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What is Multiplication – part VIII

Posted on 2009/04/26 by Bert Speelpenning

In this series of posts, we looked at various embodiments of multiplicative structure.  Each involves ideas about multiplication.  How are these ideas learned? From reading this blog, you will have gathered that I mean the question “how is an idea … Continue reading →

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What is Multiplication – part VII

Posted on 2009/04/22 by Bert Speelpenning

In the prior post we looked at the array model for multiplication.  At least, this is the way we usually talk about it: as if it is already clear what multiplication is, and we just want a way to show … Continue reading →

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What is Multiplication – part VI

Posted on 2009/04/20 by Bert Speelpenning

In our series of posts looking at multiplicative structures I wouldnt want to leave out what is often called the area model, though I think array model is a better fit.   As I suggested in a prior post, the notion … Continue reading →

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What is Multiplication – part V

Posted on 2009/04/20 by Bert Speelpenning

Numbers provide a way to mark events.  This can usually be done in more than one way.  We can “slice” reality in more than one way. The picture above shows a common way to look at a single stock on … Continue reading →

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What is Multiplication – part IV

Posted on 2009/04/19 by Bert Speelpenning

In the previous post we looked at man hours.  Man hours are strange beasts – but not too strange – that represent the result of multiplying men and hours.  They make sense in the context of billing, and when sizing … Continue reading →

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What is Multiplication – part III

Posted on 2009/04/19 by Bert Speelpenning

In the first installment of this series we looked at multiplication as what happens when you have a number of groups and each group consists of an equal number of members.  Our example was 3 rolls of Mentos, where each … Continue reading →

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What is Multiplication – part II

Posted on 2009/04/18 by Bert Speelpenning

For our second installment in the series, I want to look for an embodiment of the idea of multiplication that’s quite different, at least on the surface, from the idea in the previous post of multiplication as 3 rolls of … Continue reading →

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