Constraints, which are mathematical concepts, are also present in every day’s life. They are defined as limitations. A set of basic equations can determine the components of a schedule such as the duration of an event, a deadline for a task. But there are factors that cause these limitations. All is needed is some elementary algebra. Suppose Tony needs to determine the right time to write an essay, by that we mean the start and end time. What are the concerned variables? For sure we will consider opportunity cost. Now, to be accurate: is the next task a schoolwork or another type of task? Another dimension is the type of schoolwork; beside the subject. So as you see, an simple problem can be easily complicated.