python does the hard part of evaluating it down to single value python will keep evaluating parts of the expression until it becomes single valueas shown here( (( ( ) (( ( ) ( these rules for putting operators and values together to form expressions are fundamental part of python as programming languagejust like the grammar rules that help us communicate here' an examplethis is grammatically correct english sentence this grammatically is sentence not english correct the second line is difficult to parse because it doesn' follow the rules of english similarlyif you enter bad python instructionpython won' be able to understand it and will display syntaxerror error messageas shown here file ""line syntaxerrorinvalid syntax file ""line syntaxerrorinvalid syntax you can always test to see whether an instruction works by entering it into the interactive shell don' worry about breaking the computerthe worst that could happen is that python responds with an error message professional software developers get error messages while writing code all the time