Exploring and Creating Mathematics Part 3: Investigating Powers using Pascal’s Triangle

Before reading this post, you might want to see the other two posts in the series:

Post 1 – Creating and Exploring Mathematics: How many different directions can we take a topic in 15 minutes?

Post 2 – Discovering and Creating Mathematics Part 2: Does investigating problems make it easier to pose interesting problems?

Whenever we get a chance as mathematics educators, I think it’s great if we can explore and discover our own mathematics. Of course it’s almost always been created before but I don’t see how can we ask students to investigate and explore if we’re not prepared to do so?

So today I spent a few hours investigating powers using a binomial theorem/Pascal’s triangle approach. Would love to see how other maths teachers would investigate this given the chance. Here’s some interesting stuff I discovered today:

1. The sum of row n of Pascal’s triangle is equal to 2^n.

2. Odd powers of 4 always have final digit ending in 4; Even powers of 4 always have final digit ending in 6.

3. The first four powers of 11 follow exactly the same digits in Pascal’s triangle. E.g.

11, 121, 1331, 14641, …

After that, the pattern doesn’t work. This is a great example to show why proof and reasoning are important in mathematics.

4. The sum of the digits of powers of 11 are always even.

As a side note, one thing that occurred to me is that mathematical writing is generally quite boring. Don’t get me wrong – the mathematics itself is interesting – its just the writing in between. Hence, at certain points I’ve highlighted the “aha” moments by directly writing it. I know that this isn’t convention in mathematics articles but I feel like it would be a great thing to promote with students. Especially during journaling.

B1

B2

B3

B4

B5

B6

B7

B8

B9

B10

B11

Advertisements
This entry was posted in Investigations and tagged , , , , . Bookmark the permalink.

2 Responses to Exploring and Creating Mathematics Part 3: Investigating Powers using Pascal’s Triangle

  1. great to see some new posts! I like your idea about us as teachers doing our own investigations too. I (re)did an old IB maths investigation a few weeks ago – looking at patterns in stellar numbers. That’s quite a good one for patterns [http://ibmathsresources.com/2015/01/20/stellar-numbers-investigation/]. Loads of ideas for patterns in pascal’s triangle – I like this pdf [http://www.danielmathews.info/articles/pascal.pdf] – especially the binary patterns….

  2. Definitely agree – I taught SL when stellar numbers was one of the Type I tasks to choose from – great task. I’ve not been on your site for a while because I thought you’d stopped blogging too – just been on and read some great recent posts! Thanks to the link to the Pascal Triangle PDF – instantly hooked by the introduction on the number of odd entries in each successive row of Pascal’s triangle – interesting way to look at it.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s