@Malini
To help children to improve in studies with VK you can use Study serum, balance serum and golden sunrise.
Mood up serum is given to a person who has low feelings, depressed mood, disheartened because of poor study pattern (if a student). so please check if the child is so then add Mood up serum too.
These serums will take care of Retention of learning, focus, concentration and memory.
To get good marks in exams send GOLDEN SUNRISE to his books, stationary, room where he studies, exam hall, invigilators, exam sheets, question papers, result and marksheet.
For disinterest in particular subject like maths and hindi or any other subject Balance serum and GOLDEN SUNRISE energy will take care.
loosing marks are out of lack of focus or over confidence of a child. The above mentioned energies will take care in improving focus and concentration of the child.
If you feel that are behavioural changes like mannerism which need attention, you can check BACH FLOWER REMEDIES too else GOLDEN SUNRISE will take care.
Do share your further question and experience with the above mentioned Serums.