For many students, solving numerical problems is often the most difficult part of chemistry course. thisproblem can be found in learning the mole concept, whereas it is most important for all calculation of chemistry. learnig of the mole concept can be done by the factor label and formula method. the factor label method uses in the units associated with number as a guide in working out the arithmetic, while the formula method uses one and more formula. Learning by the factor label method has preparedness for meaningful learning and ability of thinking compared to the formula method. The results of study of the mole concept with the factor label method is higher than the formula method.