There can be many reasons that your child is having difficulty with focusing within the classroom. Please consider a meeting of the school IEP team to discuss her academic and behavioral repertoire within the classroom. Together all should come up with some information and strategies that could be helpful.
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You asked this question in October. By that time many of the children have settled into the routine of school. Still some children struggle to make the adjustment from a summer vacation without many demands to the daily demands for focus and effort that comes with the new school year.
How old your child is, your relationship with the current teacher, and whether you are seeing some of the same behavior at home should be factors you consider. Some children just happen to be 'late bloomers', and the best thing you can do is to lovingly support them while giving them a chance to mature.
If you have a positive, supportive relationship with your child's teacher, ask her/him what issues have been observed in the classroom and listen to what particular recommendations are offered to support your daughter both at school and at home. While we teachers cannot diagnose medical conditions, we have seen a lot of children and are pretty accurate at identifying children whose behavior indicate a need for further attention and support.
Should this behavior be consistent over time and place, you might want to express your concerns with your child's pediatrician. There are so many reasons for a child to appear unfocused and not motivated in school. Some are easier to 'tease' out, such as a child not sleeping well. Others are much more difficult like ADHD or a seizure disorder.
Once any possible medical issue has been either been identified or eliminated, your school's educational team is a good resource to use. Many parents don't realize that they can and should initiate a referral for possible assessment for their child.
As a parent, be the supportive advocate who expresses the concerns your child probably cannot yet articulate.