Multiplication with lines

Another topic my wife showed me. Multiplication by drawing lines. As she pointed out, this would get cumbersome (or worse) with numbers of several digits, but it’s interesting anyway.

Here’s a video.

Here’s a written example.

Why does this work? Nobody knows! OK, somebody does. This site also suggests how to do this multiplication when some of the digits are zero. How do you draw a “missing” line? Dots easy!

Scientific Test: Dog is man’s best friend

You’ve heard those warnings after watching something potentially dangerous on TV: “blah blah blah done by professionals. Don’t try this at home”.

Well, here’s something you can try at home.

Hypothesis: A dog is truly man’s best friend.

Experiment: Perform the following steps:

1. Put your dog and your wife in the trunk of the car for an hour.
2. When you open the trunk, which one is really happy to see you?

(Modified from an email from my wife via a friend via who-knows.)

Celebrate “Pi Day”

Should be a national holiday!

Enjoy Pi Day.

Secret Codes – Updated

Earlier there was Dad’s Secret Code. Then there was Mom’s Secret Code.

But before all that, there was Fletcher Pratt’s Secret and Urgent: The story of codes and ciphers. This was one of the book highlights of my boyhood days. This is an interesting, and to some of us, exciting book to read. It gives some history of codes and ciphers, and also gives some examples. Since it was originally written during World War II, it doesn’t have much on WWII code efforts. That would have to come later in other books. I wasn’t the only one impressed by this book.

I was going to suggest some related books on codes and ciphers, but at the moment my memory won’t cough them up.

Anyway, start with Pratt’s book and work toward the present. There are some interesting books that do give insight into WWII and more recent code work. It is an amazing area of mental work. Some have suffered mental breakdowns because of the stress involved. But it is also a fertile area in recent mathematical work. Modern computer communication and data storage would not happen without information encodings of various kinds.

It’s an interesting area of study, with problems for all levels of skill and knowledge. Now, if I could only break Dad’s Secret Code.

[Update: Two books that I couldn't recall earlier are: The Code Breakers by David Kahn, and The Code Book by Simon Singh. A search on Amazon.com for "Code Breaker" as a title yields several books. A search by subject should give even more. Unir sha ernqvat nobhg pbqrf naq pvcuref!]

Downloading the Internet

Most of you have downloaded files from the Internet at one time or another.

But, have you tried downloading the whole Internet?

You might have to wait a bit, and have an extra disk or two handy.