Tag Archives: abacus

Sideband #66: Abacus Multiplication

Today’s earlier post got into only the beginnings of abacus operation — mainly how to add numbers. To demonstrate how they have more utility than just adding and subtracting, this Sideband tackles a multiplication problem.

This also illustrates a property of abacus operation that doesn’t arise with addition. With pen and paper, we multiply right-to-left to make carrying easier. Because of the way an abacus works, multiplication has to work left-to-right.

The process is simple enough, but has lots of steps!

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Abacus and Slide Rule

Ye Olden Tools of Yore

I’ve been meaning to write an Abacus post for years. I used one in my first job, back in high school, and they’ve appealed to me ever since. Many years ago I learned there were people who had no idea how an abacus worked. Until then I hadn’t internalized that it wasn’t common knowledge (maybe a consequence of learning something at an early age).

Recently, browsing through old Scientific American issues before recycling them, I read about slide rules, another calculating tool I’ve used, although, in this case, mainly for fun. My dad gave me his old slide rule from when he considered, and briefly pursued, being an architect.

So killing two birds with one stone…

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Sideband #44: CG Theatre

Sideband ElectrodeBack on my first Sideband post, I wrote that, “Sideband posts are miscellaneous thoughts that accompany the main thread of posts. Think of them as small paths that meander off the main road. Some branch off, go a short ways and die after a short while. Others are scenic trails that follow along the main road.”

They never quite achieved that vision, so this year one goal is getting Sidebands back on track with that original “mission statement.”

And I’m going to start with fun topic: computer-generated 3D images!

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Bab’s Drive-In Dairy

(c) Google EarthToday, of course, is the last day of September. For a variety of reasons, it’s always been one of my favorite months, and it’s always bugged me slightly that September — having only 30 days — is one of the short-changed months. August around here is usually hot, muggy and buggy, so I’d be fine with Congress passing a law to give one of August’s days to September.

And pity poor February! Not only stuck with being the shortest month (a month frequently dark and very cold), but saddled with the responsibility of having to keep an eye on the calendar to even know how many days it has!

Perhaps Congress could also declare February to be National February Month!

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