Mathematica Tutorial: Notebooks And Documents - Wolfram Research

6 Notebooks and DocumentsAfter you have edited the output, you can send it back as further input to the Mathematicakernel.When you do computations in a Mathematica notebook, each line of input is typically labeledwith In@nD :=, while each line of output is labeled with the corresponding Out@nD =.There is no reason, however, that successive lines of input and output should necessarilyappear one after the other in your notebook. Often, for example, you will want to go back to anearlier part of your notebook, and reevaluate some input you gave before.It is important to realize that in most cases wherever a particular expression appears in yournotebook, it is the line number given in In@nD := or Out@nD = which determines when the expressionwas processed by the Mathematica kernel. Thus, for example, the fact that one expressionmay appear earlier than another in your notebook does not mean that it will have been evaluatedfirst by the kernel. This will only be the case if it has a lower line number.Each line of input and output is given a label when it is evaluated by the kernel. It is theselabels, not the position of the expression in the notebook, that indicate the ordering of evaluationby the kernel.The exception to this rule is when an output contains the formatted results of a Dynamic orManipulate function. Such outputs will reevaluate in the kernel on an as-needed basis long