This study examined students’ difficulties related to variables at grade nine using a diagnostic test designed for this purpose. It also examined the persistence of these difficulties by giving the same test to high-school students and comparing the difference in students’ performance at ninth and twelfth grades. Results revealed that students have several difficulties when dealing with variables. Some of these difficulties are not attaining the ability to determine the role of the variable, assuming that a literal symbol stands for a single value, defining variables nominally not quantitatively, not attaining the meanings of basic expressions as ??,???… in addition. It also revealed the persistence of these difficulties throughout highgrade levels.

Keywords : Variables, Literal Symbols, Difficulties, Misconceptions.