Saturday’s National Math Festival is billed as “the first national festival dedicated to discovering the delight and power of mathematics in everyday life.” Organized by the Mathematical Sciences Research Institute and the Institute for Advanced Study in cooperation with the Smithsonian Institution, the free event runs from 10 a.m. to 4 p.m., with dozens of lectures, demonstrations, performances and games at museums and other sites around the Mall. Here’s a glimpse of some of the topics:

● How to add, subtract and multiply using the base-20 system of the ancient Mayans.

● How to measure the density of a supposed diamond to see if it’s actually a piece of quartz.

● Why the “God’s number” for the Rubik’s cube is 26 — meaning every cube can be unscrambled in 26 moves.

● How many grains of sand the Greek mathematician Archimedes estimated it would take to fill the universe (and how he designed a heat ray that could burn the sails of approaching enemy ships).

● How teachers can use the computer game Minecraft as an educational tool.

● How drag racers are able to accelerate faster than the pull of gravity.

● How to use math to assign the lanes fairly for BMX racing.

● Why Malaysian fireflies are able to synchronize their flashing, with thousands at a time lighting up in unison.

● How to measure the sun, using a safe-for-viewing telescope.

● Which traditional African arts are based in mathematics.

● How to take forensic measurements to learn when, at what age and maybe how a person died.

And a lot more. For a schedule and further information, go to www.mathfest.org.