scalar quantity A scalar quantity is completely specified by a single value with an appropriate unit and has no direction. Some examples of scalar quantities are volume, mass, speed, and time intervals. vector quantity A vector quantity is completely specified by a number with an appropriate unit plus a direction. Parallelogram method In this method, the two vectors are drawn starting form the common origin. And a parallelogram is constructed using these two vectors as adjacent sides. The resultant is the diagonal drawn from the comm origin.