An experiment was conducted over three recent semesters of an introductory calculus course to test whether it was possible to quantify the effect that difficulty with basic algebraic and arithmetic computation had on individual performance. Points lost during the term were classified as being due to either algebraic and arithmetic mistakes (ALARMs) or to difficulty with the calculus material. The experiment found that over 65% of all students sacrificed at least one-third of a letter grade specifically to ALARMs, while nearly 20% sacrificed two-thirds of a letter grade.