Your daughter is probably bored with what she is currently learning.  My son would always wait till the last 5-10 minutes to complete his work before going to recess.  I spoke with his 1st grade teacher, who would write unpleasant comments about his work habits in his "Agenda".  I had mentioned to her, that if it doesn't take him the same amount of time to complete the work; then maybe, just maybe, his learning process is above his peers.  My son is currently enrolled in a Charter School.  He is now in the 7th grade, but learning in the 9th grade level.  Best of luck to you & your daughter.  The mind is a terrible thing to waste.  You might want to try anything to help her enjoy the learning process.

sit by the side of her when she do her homework encourage her by giving small gifts and tell her that she is very smart she will finish her homework fast explain her maths word problems you too do the sums in a paper sitting by the side of her have some bet with her make study as a playful thing to her by your behavior always encourage her she will become alright

let me tell please about her mental ability...
is she genious or average student in class?
what are the comments of teachers about her?

@Rabail: These are the answers of your question about her,
1- In class, She is below average student.
2- Commentts fo teachers "she does not have any concept about Math, science etc etc"
One more comment: " She does not respond most of the time when teacher asks her any question....probably her mind is somewhere else"

Hope this answer your questions.