What are the "numbered days" (ayyam ma'dudat) mentioned in the āyah?

Imām Ibn al-Jawzī (d. 597/1201) summarized the scholars' opinions in his book "Zād al-Masīr" as follows:

1. The days of Tashrīq (11-13 Dhu al-Ḥijjah). [Ibn ʿUmar, Ibn ʿAbbās, al-Ḥasan, ʿAṭāʾ, Mujāhid, Qatādah, and others]
2. The Day of Sacrifice (Yawm al-Naḥr) and the two days following it (10-12 Dhu al-Ḥijjah). [Narrated from ʿAlī and Ibn ʿUmar]
3. The first ten days of Dhu al-Ḥijjah. [Saʿīd ibn Jubayr, al-Nakhaʿī]