Reading, writing and ’rithmetic may still be the “big three” building blocks of learning, but teachers and administrators are increasingly finding themselves incorporating another big three into their education curriculums and job responsibilities: iPhone, iPad and Android apps.

Although not yet as ubiquitous yet as conventional computer programs, countless mobile apps have made their way into the classrooms and administrative offices of K-12 and higher education. There are even companies – and apps – that help schools and educators create their own mobile apps customized to meet explicit needs or achieve specific objectives.

For example, a company called Crescerance works with K-12 schools to create made-to-order apps for iPhones, Android and even Blackberry mobile devices. Another company, CollegeMobile, specializes in offering similar mobile app development for higher education. There’s even an app – albeit for Macintosh computers – that enables teachers to create their own, customized, multimedia iBook textbooks for iOS mobile devices.

Teachers and administrators who use customized and off-the-shelf mobile apps often find them invaluable. Mary Brown, a principal Wittenburg Elementary School in Taylorsville, NC, says, “I use Evernote for all my [classroom] observations because it’s quick and easy, and I can include real-time pictures and video from that observation.” It is the perfect observation documentation tool. “We also use GoSkyWatch Planetarium for our astronomy units, and we are all [students, teachers and administrators] mesmerized by it. It truly does engage kids. After a lesson, the students will go outside and see the real night sky and look for stars and constellations.”

Kris McCarthy, a fourth-grade math and science teacher at Wyoming Seminary Lower School in Forty Fort, PA, regularly uses eClicker in her classroom to get real-time feedback from her students.“It allows me to create online tests or assessments and poll the students,” she explains. “I use it a lot, and the kids love it. I’ve used it as an alternative to paper-and-pencil science tests and quizzes. You can even use it to print out the kids’ scores. “Another [app] that I know is very popular is Math Bingo. It makes it fun for kids to practice their math – in the classroom and at home – by turning it into a game they can play using different avatars.”

Whether they are games that educate, tools for administrators or bridges connecting schools and parents, mobile apps have become an integral part of education. There are literally hundreds, if not thousands, of education apps out there, but here’s a sampling of some of the most interesting and popular ones for iOS and Android devices.