The closer we get to Minus the Bear’s Tuesday show in Bend, the more the question has come my way.

“Hey Ben,” says a disembodied voice from some other cubicle in the newsroom. “What is math rock?”

Fair question.

There certainly have been bands that embody math rock more than Minus the Bear, but if you take a spin through the Seattle-based quintet’s 2007 album “Planet of Ice,” you can hear the telltale signs of the genre: complex rhythms, sudden tempo shifts, guitars that chime and gurgle, ethereal melodies that seem to drift in and out of consciousness.

It’s hard to grasp, like saying something tastes like purple. But listen to Minus the Bear, and listen to the tones as they ricochet around your brain. Listen for the angles in the music. They’re there.

They’re there in abundance on “Planet of Ice,” released last summer on respected indie label Suicide Squeeze Records. But unlike the urgent, spastic nature of Minus the Bear’s first couple of albums, “Planet” sounds cold, calculated and almost detached, as if the musicians (including former members of hardcore bands Botch and Kill Sadie) are slaves to the sound, rather than the other way around.

Keyboardist Alex Rose put it pretty well in an interview last month with The Observer, the University of Notre Dame’s student newspaper: “I usually say it’s classic rock of the future.”

Indeed, it is. There’s guitars aplenty and a willingness to jam ascendingly, but also an electronic element that makes Minus the Bear seem even more forward-thinking than your average math rock band.

Whatever that is. Minus the Bear, Portugal. The Man, The Big Sleep ; 8 p.m. Tuesday, doors open 7 p.m.; $16 plus service charges in advance, $18 at the door. Advance tickets available at Ranch Records (389-6116) in Bend and through Ticketswest at www.ticketswest.com, 800-992-8499, and the Safeway at 642 N.E. Third St., in Bend.; Domino Room, 51 N.W. Greenwood Ave., Bend; www.random presents.com.