Unable to update version of WordPress

Hello, I have purchased and downloaded Clean Education Pro and have my site almost completely finished, but today I tried to update to the latest version of Wordpress and I am unable to. I get the following error message:

Downloading update from https://downloads.wordpress.org/release/wordpress-4.8.1-partial-0.zip… Unpacking the update… The update cannot be installed because we will be unable to copy some files. This is usually due to inconsistent file permissions.: wp-admin/includes/update-core.php Installation Failed

I have not touched the includes folder or the update-core file so I am wondering why there is a problem with these files. Please advise if there is a glitch with the files I downloaded and/or how to fix this so I may update to the latest version of Wordpress. Thank you