Dr. Math FAQ: What Are Leap Years?
2012 is a leap year, so this month ends on Wednesday,
In the leap year of 1996, the Forum began a free ask-an-expert
service for math students and their teachers. Since then, Ask
Dr. Math has helped millions understand why some years have 366
days, plus lots more mathematics about calendars, including
how to take leap years into account when reasoning the day
of the week one year forward from any given date
how to determine the day of the week for any date
the surprising commonality of Friday the 13ths (2012 has
the maximum number, with two more to go)
PoW taking place: math problem-solving moment of the week
"The other thing I loved about this PoW was that when I was
reading the solutions I was really surprised by how many ways
there were to think about the problem. Silly me, I thought my
way was the obvious and only way... but of course I was wrong.
I loved reading all of the ways you thought of the problem,
and was really impressed that Student fourteen from Caughlin
Ranch Elementary School shared two different ways to solve
- Max, commenting on the Pre-Algebra PoW's Latest Solution
Math Teachers' Circle Workshops
Apply now for the summer workshops "How to Run a Math Teachers'
Circle" and "Math Teachers' Circle Immersion."
Math teachers' circles put middle school math teachers in
regular contact with mathematicians to work collaboratively on
mathematical problem solving in the context of rich problems.
The deadline for these professional development opportunities,
run by the American Institute of Mathematics (AIM), is Friday,
16 March, 2012.
AIM recently posted some classroom-ready
The Handshake Problem
All Possible Diagonals
Dots and Boxes
Freely download these PDFs, developed by James Tanton and other
master teachers, from here:
Now taking place: math education conversation of the hour
"I feel very lucky to have gotten a great educator in high
school mathematics. In addition to teaching us the concepts,
formulas, and rules of mathematics, she listened to us in the
hallways and in class and even in the lunchrooms, and picked up
on some problems we experienced in our daily lives. She would
then utilize that in class, and mathematically model some of
the problems we experienced. In doing this, she even managed to
slip in some math that was not on the exams, which stuck with
me for the past 12 years."
- John, posted to the math-teach discussion
Lipson's Lego Sculptures
Self-described "professional nerd" Andrew Lipson has
constructed M.C. Escher drawings and other mathematical
forms — out of Legos®.
Lipson's Lego Sculptures is the latest Mathematical Imagery
album of the American Mathematical Society (AMS), which lets
you send images of his creations as e-postcards.
Have you constructed a mathematical form using Legos? The AMS
invites you to share a photo of it on Facebook:
Other Mathematical Imagery albums of the AMS include
shapes and tilings by Edmund Harriss
simulated snowflakes by David Griffeath and Janko Gravner
woven beads by Gwen L. Fisher
origami by Robert J. Lang
For more of Lipson's brick-by-brick creations, check out