for syntax errorsthe error messages don' help much the most common messages are syntaxerrorinvalid syntax and syntaxerrorinvalid tokenneither of which is very informative the runtime error you are most likely to make is "use before def;that istrying to use variable before you have assigned value this can happen if you spell variable name wrongprincipal interest principle rate nameerrorname 'principleis not defined variables names are case sensitiveso latex is not the same as latex at this pointthe most likely cause of semantic error is the order of operations for exampleto evaluate / pyou might be tempted to write pi but the division happens firstso you would get / which is not the same thingthere is no way for python to know what you meant to writeso in this case you don' get an error messageyou just get the wrong answer glossary assignment statement that assigns value to variable concatenate to join two operands end to end comment information in program that is meant for other programmers (or anyone reading the source codeand has no effect on the execution of the program evaluate to simplify an expression by performing the operations in order to yield single value expression combination of variablesoperatorsand values that represents single result value floating point type that represents numbers with fractional parts integer type that represents whole numbers keyword reserved word that is used by the compiler to parse programyou cannot use keywords like ifdefand while as variable names mnemonic memory aid we often give variables mnemonic names to help us remember what is stored in the variable modulus operator an operatordenoted with percent sign (%)that works on integers and yields the remainder when one number is divided by another operand one of the values on which an operator operates operator special symbol that represents simple computation like additionmultiplicationor string concatenation rules of precedence the set of rules governing the order in which expressions involving multiple operators and operands are evaluated statement section of code that represents command or action so farthe statements we have seen are assignments and print expression statement