Equal parts action and humor add up to a wholly entertaining introduction to simplifying fractions, in this one-of-a-kind math picture book story. When a valuable fraction goes missing, George Cornelius Factor (a.k.a. GCF) vows to track it down. Knowing that the villainous Dr. Brok likes to disguise his ill-gotten fractions, G.C.F. invents a Reducer—half ray gun, half calculator— that strips away the disguise, reducing the fraction to its lowest common denominator and revealing its true form. With the Reducer in hand, George seeks out Dr. Brok in hopes of retrieving the missing fraction. David Clark’s illustrations are packed with humorous details as well as clearly defined fractions and their corresponding reduction equations.