To calculate the overall star rating and percentage breakdown by star, we don’t use a simple average. Instead, our system considers things like how recent a review is and if the reviewer bought the item on Amazon. It also analyzes reviews to verify trustworthiness.
Cannot zoom in, makes the reading experience anything but good. I don't know if it's due to the app's limitation, or the publisher, the zoom feature is in the app but greyed, so unusable. I can double click images to zoom in, but just barely. A pdf would be much easier, zoom in a little and glide over each section.