Mr. Higgins’ Blog

Sep 2nd, 2006 by Mr. Higgins

After my first week of teaching I feel the confidence flowing and can tell that many of the students agree with my style and know that I care. I’m working more on respect than the students “liking” me because of my inexperience. Especially in my AP Computer and Algebra II class I wanted to establish a dominant first impression. So far it seems to have worked. I am already noticing students saying “hi” to me in the hallway, coming to me with help, and asking questions because they are not intimidated by what I might say in return.

I know it is only a matter of time before a student challenges my authority, but that is life. I appreciate those of you who have made comments because it makes it easier to reflect on my experience. I just need to keep up the hard work and remember to stay on an even emotional and mental playing field. This will allow me to concentrate on the students a little more as time goes on, rather than my own challenges.

Interesting extracurricular activity I gave my students in Algebra II…

They were to find a UPC code and show me it is valid my using math. For those of you that don’t know, there is a neat mathematical formula that is involved in validating UPC codes.

This UPC code above has actually 11 digits. The 3 on the left is the 1st digit while the 11th digit is a 1. The 7 on the far right is called the check digit.

The formula is as follows:

3 x (Sum of Odd Positions (i.e. 1st, 3rd, 5th,…digit)) + (Sum of Even Positions) = Z

You then take the number Z and subtract it from the next multiple of 10.

Example for UPC seen above

3x(3 + 0 + 4 + 6 + 6 + 1) + (0 + 7 + 6 + 0 + 0) = 73

Next multiple of 10 is 80. So 80 – 73 = 7. The check digit shows this UPC code is VALID.

Posted in Computer Science, Math, Teaching

6 Responses to “Confidence is flowing…”

on 03 Sep 2006 at 3:14 pm1Alfred Thompson

I love it. I can think of several ways to make that into an early coding exercise in a programming course as well. I’m going to write up a couple of ideas around that and point people here for the source/background.
on 04 Sep 2006 at 10:59 am2Computer Science Teacher - Thoughts and Information from Alfred Thompson

Mixing math and Computer Science…

I am always on the look out for new and interesting projects to use in programming classes. Well I hope……
on 23 Oct 2006 at 9:39 pm3Jennifer

NO WAY _- I didn’t know that about UPC codes —

sooo sooo cool.

Thanks for sharing.

Jennifer Wagner
http://www.womenofweb2.com

ps — I found you link from your comment on the K12 conference!!
on 12 Jan 2007 at 11:51 am4Siebe Tolsma

That’s pretty cool.

By the way, either I’m completely brain dead, or your example has a mistake. 3+0+4+6+6+1 is 20, times 3 is 60, plus 6+7 is 73, not 43. Same answer though (80-73=7).
on 13 Jan 2007 at 11:52 pm5Higgy

Thank you for correction.
on 28 Dec 2007 at 11:45 pm6Higgy’s Blog » Blog Archive » Backbone Programs of AP Computer Science A

[...] UPC Code – This is explained in a previous blog entry. [...]