My younger brother also use this app which is in class 11 ans he perform well in almost all subjects.According to me byju's application is best for kids of age between 9-20 because between these ages the load of education is in extream level. So to provide them some relaxation this app is best it clears all the topics related to any class or any subject from this student can learn easily rather than other place but parents should give attention to there ward in this app. In this app the chapters are divided on the bases of level after study. one chapter the test is taken by the app if the test is not passes by the stydent the student will not permitted to go into other chapter or level and if parents has any excuse then they directly contact to there staff or teachers again I remember you my younger brother which is in class 11 also use this app . And he perform well in all subjects