This is my first post here. I have benefited a lot from this forum and I hope I will be able to get an answer for my query

My daughter is going to Turku International school.
For Mathematics, they did 2 books this year.
But apparently, some kids got EXTRA books as well from the teachers.
Now I am a bit confused about this one. What is the criteria for getting extra books? One of the kids completed 5 maths books this year. How is that possible?
Did the child keep doing the exercises on her own? What about the exercises done at class then if she has already done that?
The home work notification we receive from teacher, that explains that we have done this chapter today and so and so is for homework, so what about the child with 5 maths books? As my understanding is that the child has completed those exercises already.
My daughter always wanted to do more exercises on her own as well but I did not let her as I thought she should keep up with her class mates, but if kids are allowed to, I should let her.
Thanks in advance and I hope my query is clear

Regards