At Old Mill Math Team today they worked on a problem that Jeff liked so much he had to share:

All counting numbers are arranged in the triangular pattern as shown by the first four rows:

1
2  3  4
5  6  7  8  9
10 11 12 13 14 15 16
and so on.

Q: What is the first number in the 13th row? Why?
(Extra credit: what’s the first number in the 1,001th row?)

P.S. Park parents: your brand-new Math Club will launch on Friday 3/22!  Give Shawn & Nicole & Erik and your principal a big “thanks!”