This is SAPIX's Basic Skills Training for 6th graders. It consists of six books, starting in February and running through July. By working through one page a day, you can significantly improve your calculation skills. It is said that this alone covers a certain level of entrance exam questions. This is a used item, as it was used by a child, so there is a feeling of use. There are a few days in each month with writing, such as intermediate calculations, as shown in the photos. Please refrain from purchasing if you are looking for a pristine item. No claims and no returns accepted. Thank you for looking.