Math Connections in the Digital Age: Basic Calculus covers both differential and integral calculus. The lessons are introduced with the use of both algebraic and graphical approaches. As intended, realistic approach of teaching is used on examples which are arranged from easy to complex, presented in a step-by-step manner, and based on real-life situations. This textbook provides the necessary background and foundation for much more advanced theoretical and practical aspects of disciplines that will be taken under the STEM Program. The learning competencies in the textbook comply with the K to 12 curriculum for senior high school. This textbook teaches the students how to determine the limit of a function, differentiate and integrate algebraic, exponential, logarithmic, and trigonometric functions in one variable, and to formulate and solve problems involving continuity, extreme values, related rates, population models, and areas of plane regions.