## Girls’ Angle Bulletin, Volume 11, Number 4

Betsy Stovall, assistant professor of mathematics at the University of Wisconsin-Madison, kicks off Volume 11, Number 4 with a wonderful interview. Her story of how she became interested in math is inspiring. She also describes one of the nifty problems that sparked her interest in math when she was a student. If you haven’t seen it before, it’s well worth thinking about.

Deanna Needell adds a second installment to her column The Needell in the Haystack, this time about filling in missing entries of a matrix. She describes an application to the study of Lyme disease. To fully understand Prof. Needell’s articles, one does have to be familiar with matrices. For those of you who don’t know about matrices, we included a very brief introduction to matrices intended to help reader’s unacquainted with the concept at least feel good enough about them to read Prof. Needell’s Bulletin contributions. Her articles are very much worth reading even if you don’t know about matrices.

Emily and Jasmine embark on a new adventure resulting from a graphic design project themed on the circle. The assignment inspired Emily to create a design of radiating circles. To create the design, she discovered some neat math. This new journey was inspired (in a somewhat indirect way) by work of students at the Buckingham, Browne, and Nichols Middle School.

Anna makes progress on her current problem by characterizing those $m$ for which ${2m} \choose m$ is congruent to 1 modulo 3.

Lightning Factorial authors an installment of Math In Your World, analyzing how to intercept an incoming tennis shot as quickly as possible.

Next, Girls’ Angle member Allie presents her wonderful inductive proof of a conjecture she came up with at the Girls’ Angle club regarding the largest number expressible using N ones, addition, multiplication, and parentheses.

We round out the issue with some Notes from the Club.

We hope you enjoy it!

Finally, a reminder: when you subscribe to the Girls’ Angle Bulletin, you’re not just getting a subscription to a magazine. You are also gaining access to the Girls’ Angle mentors.  We urge all subscribers and members to write us with your math questions or anything else in the Bulletin or having to do with mathematics in general. We will respond. We want you to get active and do mathematics. Parts of the Bulletin are written to induce you to wonder and respond with more questions. Don’t let those questions fade away and become forgotten. Send them to us!

We continue to encourage people to subscribe to our print version, so we have removed some content from the electronic version.  Subscriptions are a great way to support Girls’ Angle while getting something concrete back in return.  We hope you subscribe!