Students in Melissa Williams' kindergarten class at the Westminster School in Atlanta, Georgia, practice connecting quantities to written numbers — a key part of number sense. Credit: Holly Korbey for ...

Katie has a PhD in maths, specializing in the intersection of dynamical systems and number theory. She reports on topics from maths and history to society and animals. Katie has a PhD in maths, ...

Your support goes further this holiday season. When you buy an annual membership or give a one-time contribution, we’ll give a membership to someone who can’t afford access. It’s a simple way for you ...