Visitors operate a viewing camera on a robotic arm that extends from a 3-D version of the International Space Station. Here they are exploring the coordinate system as a way to locate objects in two-dimensional space. (Oscar Williams/MathAlive!)

What: MathAlive!

Where: The Ripley Center, 1100 Jefferson Dr. SW, right next to the Smithsonian Castle. Go down the stairs to the International Gallery.

When: Every day 10 a.m.- 5:30 p.m. until June 3.

How much? Free.