width once variable is assigned valuethe variable can be used in place of that value the response to the expression width is the same as if its value had been entered the interpreter does not print value after an assignment statement because the value of the expression on the right is not lost it can be recovered if you likeby entering the variable name and we did above try each of the following linesheight area width height area the equal sign is an unfortunate choice of symbol for assignmentsince python' usage is not the mathematical usage of the equal sign if the symbol had appeared on keyboards in the early 'sit would probably have been used for assignment instead of =emphasizing the asymmetry of assignment in mathematics an equation is an assertion that both sides of the equal sign are alreadyin factequal python assignment statement forces the variable on the left hand side to become associated with the value of the expression on the right side the difference from the mathematical usage can be illustrated try width so this is not equivalent in python to width the left hand side must be variableto which the assignment is made reversedwe get syntax error try width width this isof coursenonsensical as mathematicsbut it makes perfectly good sense as an assignmentwith the right-hand side calculated first can you figure out the value that is now associated with widthcheck by entering width in the assignment statementthe expression on the right is evaluated first at that point width was associated with its original value so width had the value of which is that value was then assigned to the variable on the left (width againto give it new value we will modify the value of variables in similar way routinely assignment and variables work equally well with strings tryfirst 'suelast 'wongname first last name try enteringfirst fred note the different form of the error message the earlier errors in these tutorials were syntax errorserrors in translation of the instruction in this last case the syntax was legalso the interpreter went on to execute the instruction only then did it find the error described there are no quotes around fredso the interpreter assumed fred was an identifierbut the name fred was not defined at the time the line was executed it is both easy to forget quotes where you need them for literal string and to mistakenly put them around variable name that should not have themtry in the shellfred 'frederickfirst fred first variables and assignment