## PHOTO MATH

PhotoMath, a free app, lets you take a picture of an equation and get an answer plus the steps involved. (Does not recognize handwriting.) Assuming you already have it on a screen somewhere, this is easier than re-typing the mathematical expression at sites like WolframAlpha.com. PhotoMath already has 11 million downloads for the iPhone and Windows Phone version. That’s a lot of downloads but it didn’t work for us. You try it. An Android version is coming soon.

## FASCINATING SCIENCE BITS

IFLscience.com has fascinating bits, including “21 GIFs that explain mathematical concepts.” For instance, did you know that the number Pi (3.14159 etc.), is equal to the distance traveled by rolling a wheel exactly one revolution? That distance turns (ha, ha) out to be 3.14 times the diameter. This is true no matter what size the wheel.

## BOOKS: ADD LIKE AN EGYPTIAN

“Good Math,” by Mark Chu-Carroll; \$34, from Pragmatic Bookshelf, tells the story of math from imaginary numbers to Egyptian fractions and Roman Numerals.

## EIGHT MATH TALKS TO BLOW YOUR MIND

Blog.Ted.com has “8 Math Talks to Blow Your Mind.” Did you know that the infinity of decimals is larger than the infinity of whole numbers? We thought infinity meant infinity. It bothers real mathematicians too.

## KHAN CAN

KhanAcademy’s free educational videos have been viewed 178 million times on YouTube. Now they’ve launched a “Computer Science” program that teaches kids and adults how to handle JavaScript; that’s the computer language that dominates the Web.

## DO THE MATH

You can type anything you want into the Google search bar, and the more specific the question, the better the answer. Now you can also use Google to graph equations.

## GEEK TIME

We didn’t think the \$115 price tag was worth it, but the new “4-bit Steel” watch from Cadence is already sold out. It uses a four-bit binary number system to mark the hours. You don’t need to know the binary system to read it, however, because the marks are all in the same position they would be on an ordinary analog watch. Still, the whole point is to raise your geek score.We tried a cheaper version, which sells for \$90 from CadenceWatch.com and is not sold out yet. The only drawback was no glow in the dark minute and hour hands; only the second hand glows not too useful. Programmers should really zero in on this, because the binary system is […]

## THE NEW MATHEMATICA

New version of Mathematica lets you use free form language instead of programming language.