Jessica Alba gets plain-Jane crazy for An Invisible Sign, a syrupy A Beautiful Mind redux in which the starlet sports big brown bangs and Pippi Longstocking pigtails as a young woman who copes with her beloved mathematician father’s insanity by retreating into numbers. Director Marilyn Agrelo visualizes this fixation by having graphic numerals float through the air whenever Alba’s Mona obsessive-compulsively knocks on wood. Such reductive Ron Howard cutesiness infects every inch of this tale (based on Aimee Bender’s novel), which finds Mona teaching at an elementary school where brats and parents alike blurt out inconsiderate insults, and where she befriends withdrawn student Lisa (Sophie Nyweide) and also finds a suitor in colleague Ben (Chris Messina). Alba aggressively fidgets and frowns, delivering a performance of mannered quirkiness that’s as contrived as a neighboring hardware store owner’s (J.K. Simmons) habit of wearing homemade number necklaces to reflect his emotional states. From a mushy opening animated parable to the looming specter of cancer, the film drowns itself in bathos, culminating with what’s surely the first-ever employment of the “Chekhov’s gun” principle—which states that objects spied in Act One must factor into Act Three—via a classroom ax and puddles of pee.