Western music isn't exactly overflowing with tracks about math — two rare examples include They Might Be Giants' "Nonagon" and Kate Bush's "Pi" — but Built to Spill wrote the best-ever song involving the subject anyway. On 1999's Keep It Like a Secret, the always dependable Boise, Idaho, indie rock legends delivered "Carry the Zero," a wistful, lonely, rough-around-the-edges tune about a perpetually broken relationship and affection gone unfullfilled. "Found the pieces, we counted them all alone," frontman Doug Martsch sings with a sigh to happen, sounding like Eeyore with an amp. "Didn't add up/Forgot to carry a zero." The lyrics of "Carry" are good, but its music is brilliant, with an aching, distortion-kissed guitar hook uncoiling toward the heavens before returning back to Earth and repeating the route. The now-22-year-old band hasn't released a new record in years — seventh album There Is No Enemy arrived in 2009 — but whenever it does, it's bound to be worthwhile. In the meantime, Built to Spill stops by S.F. for three consecutive shows at Slim's.