Feeds:
Posts

## 2010 MATHCOUNTS – Preston Trails Chapter

Congratulations to the many students of Dr. Andreescu’s who placed in the top 25 on the recent MATHCOUNTS chapter competition at the University of Texas at Dallas.

First rank went to a student who has been among the most regular attendees of Metroplex Math Circle in the last year, Niranjan Balachandar of Frankford Middle School.

The top 10 teams this year were:

1. Rice Middle School
2. Schimelpfenig Middle School
3. Frankford Middle School
4. Greenhill School
5. Coppell Middle School West
7. Renner Middle School
8. Murphy Middle School
9. Coppell Middle School East
10. Robinson Middle School

## Feb 27th – Jonathan Kane – Adding Fractions the Wrong Way

This Saturday we return from our MATHCOUNTS hiatus with a great talk by Dr. Jonathan Kane, co-founder of the Purple Comet Math Meet.

Dr. Kane will discuss combining of fractions $\frac{a}{b}$ and $\frac{c}{d}$ by $\frac{(a+c)}{(b+d)}$ to see what happens.  Sometimes this is what is done when combining groups of results and leads to Simpson’s paradox.  This also leads to very interesting behaviors when a teacher wants to drop the lowest grade from a collection of grades not all worth the same amount.  This talk will also touch on algorithms such as greedy algorithms where Dr. Kane will show cases where it works and cases where it does not work.

## Dallas Chapter MATHCOUNTS

Best of luck to all of the students competing today in the Dallas Chapter MATHCOUNTS competition!

## February 6 – Dick Gibbs – Partitioning and Permutations

This Saturday, February 6, 2010, Dr. Dick Gibbs will be presenting two interesting talks on “Partitioning” and “Cycle Structure of Permutations.”  Following are his descriptions.

I) Partitioning: lines by points; planes by lines; 3-space by planes; etc.  There are some nice patterns to be observed here.  There’s also the counting of regions formed by chords determined by n points on a circle — it’s (somehow) related to the 4-dimensional partitioning problem.

II) Cycle structure of permutations: lots of counting (and probability) problems here. For example: how many perms. have a given cycle structure? (pretty well-known); for how many perms. does a given pair, triple, etc. occur in the same cycle? (not so well-known — to me anyway!)..