  Differentiation is a mathematical skill applied throughout science in order
to describe the change of a function with respect to a dependent variable.
Thus, an intuitive understanding of differentiation is necessary to work with
the mathematical frameworks used to describe physical systems in the higher
levels of education. In order to obtain this intuition repeated practice is
required. This paper presents the development of DiffGame, which consists of a
series of exercises that introduce the basic principles of differentiation for
high-school students through game-like elements. DiffGame have been tested with
117 first-year students from a single Danish high school, who did not have any
prior training in differentiation. The students' learning was assessed by the
data obtained directly from DiffGame. The test demonstrated the efficacy of
DiffGame, since students at all levels demonstrate a learning gain. In contrast
to previous studies demonstrating most learning in the lower tier of students,
the middle tier of students (based on overall performance) exhibits the largest
learning gains.
