Combinations & Permutations on the CAS Classpad330

The factorial(!) button is found in the soft keyboard under the abc tab (hit the up arrow next to 'z' and the '1' turns into a '!' (like with a computer keyboard). It's probably worth looking for (or making) an eActivity to speed it up a little.

Going through the first two 3C exercises in Saddler, the easiest way I've found to use the calculator is to open the softkeyboard, press cat tab, scroll to N (using the alphabet at the base of the softkeyboard), highlight nCr, press INPUT and seperate the n & r values with a comma from the hard keyboard.

(Update 1/2/2009): One of my students found another way via softkeyboard->mth tab-> calc->nCr which is a lot simpler and nPr is also there!

When you need to use multiple functions just rehit the INPUT button with nCr still highlighted. Completed the whole of 3C Ex 1A & B with a combination of no calculator and this function.

viola!

I don't have my calculator books here, so this will have to do until I get back to school.

Here's a link to an index of other CAS calculator posts.

Probability & statistics

I have running battle with my lower tens getting them started but found that a game of craypots generally helped. I've bought some foam cubes from Clark rubber (2 for $3.50) 125cm x 125cm x 125cm.

I've labelled the sides storm, storm, last, fine, fine, fine in red marker so that the students can see what the weather is and decide how to play their craypots to maximise the chance of profit.

It's been great to see students find the maximum possible value, the quickest way to get out of the game (eg. the riskiest route), see their mental mathematics in action and their ability to follow a process. It's a game that's easy to set up (it needs a worksheet and a teacher with dice) and one where the class highscore can be kept to be aimed for. Here's a copy of the online version. When I remember I'll bring home my worksheet for upload.

A fair few other dice games can be found here.

It's also a bit of fun to throw the foam cubes around the room near students not paying attention.