The Prophet ﷺ would say seven takbirs in the first rakah and five in the second during the Eid prayers of Fitr and Adha.
أن النبي ﷺ كان يكبر في الفطر والأضحى: في الأولى سبع تكبيرات، وفي الثانية خمسا.
Abu Dawud (1149) narrated it from Qutayba bin Saeed, who said, Ibn Lahia narrated to us, from Aqeel, from Ibn Shihab, from Urwa, from Ayesha, and he related it as mentioned. There is well-known criticism of Ibn Lahia because of his poor memory and the confusion in his narrations, but Qutayba bin Saeed's narration from him is sound. Abdullah bin Wahb also narrated it from him, and his hearing from him was from an early period.Abdul-Ghani bin Saeed Azdi said, "When the Abadila narrate from Ibn Lahia, it is sahih," and they are Ibn Mubarak, Ibn Wahb, and Muqri, as stated in Tahdhib al-Tahdhib. Abu Dawud (1150) narrated from Ibn Sarh, who said, Ibn Wahb informed us, who said, Ibn Lahia informed me, from Khalid bin Yazid, from Ibn Shihab, from Urwa, from Ayesha, that the Prophet ﷺ said the takbir in the Fitr and Adha prayers seven and five times, apart from the two takbirs of ruku.Ibn Majah (1280) narrated it from Harmala bin Yahya, who said, Abdullah bin Wahb narrated to us, who said, Ibn Lahia informed me, from Khalid bin Yazid and Aqeel, from Ibn Shihab, with the same wording. So he combined Khalid and Aqeel, both of whom were among the shaykhs of Ibn Lahia, sometimes narrating from one and sometimes from the other, and all of it is sahih.This is what Muhammad bin Yahya Dhuhli pointed to when he said, "This is the preserved version, because Ibn Wahb's hearing from Ibn Lahia was from an early period." See Sunan al-Kubra (3/287).As for what Tirmidhi reported in Ilal al-Kabir (1/288–289) from Bukhari, that he declared it daif and said, "I do not know of anyone who narrated it other than Ibn Lahia," and what Hakim also said (1/298), "Abdullah bin Lahia narrated it alone, and Muslim cited him as a corroborating witness in two places," this is a reasonable statement, because it all rests on Ibn Lahia. However, in the view of the majority of scholars, his being the sole narrator does not harm the narration so long as one of the Abadila narrated from him, since their hearing from him was from an early period.