I just tell about byju's it is a app which is help in study I also used this app at my exam time it is ao much help ful for mee I understand all my concepts clearly on this app and score good marks it is my own exprience gys. It give us study material of all the typs and for all the class and all level student use this app and score good marks I dont have enough mony to give in institue so in 10th class I study on byju's and score 76 percent in cbse board I also suggest u to use this app at least once