´Mansur reported from Al-Hakam, from Miqsam, from Ibn 'Abbas that Umm Salamah said:` "The Messenger of Allah (ﷺ) used to pray witr with seven or five (rak'ahs), not separating between them with the taslim."
Hadith Referenceسنن نسائي / كتاب قيام الليل وتطوع النهار / 1716
Narrated Ibn Abbas: I spent a night with my maternal aunt Maimunah. The Messenger of Allah ﷺ came after the evening has come. He asked: Did the boy pray ? She said: Yes. Then he lay down till a part of night had passed as much as Allah willed; he got up, performed ablution and prayed seven or five rak'ahs, observing witr with them. He uttered the salutation only in the last of them.
Shaykh Umar Farooq Saeedi
1356. Commentary: Benefit: It is specifically the responsibility of the household members, especially the mother, to habituate young children to prayer (salah) and other virtuous deeds, and it is the right of the father or guardian to remain vigilant regarding these matters or to question them about it.
Source: Sunan Abu Dawood – Commentary by Shaykh Umar Farooq Saeedi, Page: 1356