Speaking of Google, if you visited that search engine’s homepage on February 3rd, you would have noticed that the logo was decorated with delicately colored designs. If you clicked on it, you were taken to images of Julia fractals -- swirls and shapes, kind of like the old Spirograph toy, that are the manifestation of mathematical formulas.

Why February 3rd? At first the kids and I thought we’d found the answer in that day’s comic pages, where a strip called “The Norm” pointed out that the date expressed in numerical form was 02-03-04. The real explanation turned out to be a nod to mathematician Gaston Maurice Julia, born February 3, 1893 in Sidi Abbes, Algeria. But the really cool thing was a morning spent talking and thinking about the power of numbers.

Some math websites can take you to new realms. Freelance topologist Jeff Weeks has online games including chess, tic tac toe and a mouse in the maze, all with a twist – the surfaces they’re played on curve through the fourth dimension. Amazingly, kids have no trouble figuring these out.

Ivars Peterson writes lively columns about mathematics for Science News (for grownups) and Muse magazine (for kids). Some of his finds include a guide to mathematics in “The Simpsons” (many of whose creators, apparently, hold degrees in physics and math); and an astronomer-turned-househusband who sells glass Klein bottles (the same shape used in the four-dimensional board games) on the side. You can peruse either version of Peterson’s past columns, complete with handy links, by going to www.sciencenews.org or by clicking on “Puzzle Zone” at www.sciencenewsforkids.org/ and going to “MatheMUSEments.” To find a particular topic, Google “Peterson” plus “Science News” plus the topic.

Math problem got you stumped? Over 300 math students from colleges around the country will answer your questions at the “Ask Dr. Math” page of Mathforum, from

A good way to find sites that have been prescreened (and this goes for any subject) is to check out the “Links” page of a site you like. I found the website KaBoL (which stands for “Knot a Braid of Links”) run by the Canadian Mathematical Society, on Jeff Week’s site; here you can search from among nearly 300 websites for such topics as Geometry from the Land of the Incas and amazing geometric shapes built from Legos (with computer assistance).

Personally, the sites I liked best were the ones run by and for mathematicians (amateur and “real”). Lists of math links aimed at families tend to be either “schoolish” (i.e., too much like drills) or commercial (i.e., too much like video games and TV). Still, they’re sometimes worth exploring. The National Council of Teachers of Mathematics offers Selected Web Resources featuring “mathlets” (interactive math challenges) for teachers and parents. Organized by grade and topic in a clickable chart at http://illuminations.nctm.org/swr/index.html, you can skip the boring analysis of the site you want by clicking on “Direct to SWR.”

The math game sites listed by About.com’s parenting section are more the arcade type. They include the online companion to the PBS show Cyberchase, and Coolmath.com, which has some nice math graphics as well as “study tips” (and ads). Even the government wants a crack at your budding math whiz. The National Security Agency (subject of a novel by the conspiracy-minded author of “The DaVinci Code”) has a page where kids who are into code making and breaking can explore the rooms of a Cryptic Manor to find hidden links to puzzles.

In fact, when you add it all up, once you start looking for math online the choices are almost infinite. Happy calculating!

Check these out: Google’s Feb. 3 fractal logo: http://astronomy.swin.edu.au/~pbourke/fractals/quatjulia/google.html; Four-dimensional board games: www.geometrygames.org (click on the tic-tac-toe board); The Simpsons: www.mathsci.appstate.edu/~sjg/simpsonsmath/; Clifford Stoll’s glass Klein bottles: www.kleinbottle.com; Ivars Peterson columns: www.sciencenews.org and www.sciencenewsforkids.org/; Ask Dr. Math: http://mathforum.org/dr.math/; KaBoL: http://camel.math.ca/cgi/kabol/browse.pl; National Council of Teachers of Mathematics’ Selected Web Resources: http://illuminations.nctm.org/swr/index.html; About.com’s list of math games for kids: http://childparenting.about.com/cs/mathgamesonline/index.htm?terms=math; PBS’s Cyberchase: http://pbskids.org/cyberchase/index.html; Coolmath.com: www.coolmath.com/; National Security Agency’s kid page: www.nsa.gov/programs/kids/index.html