The Messenger of Allah ﷺ would say the takbir (Allah is most great) seven times in the first rak'ah and five times in the second rak'ah on the day of the breaking of the fast and on the day of sacrifice (on the occasion of both the 'Id prayers, the two festivals).  

أَنَّ رَسُولَ اللَّهِ ﷺ كَانَ يُكَبِّرُ فِي الْفِطْرِ وَالأَضْحَى فِي الأُولَى سَبْعَ تَكْبِيرَاتٍ وَفِي الثَّانِيَةِ خَمْسًا  

"Except the two takers pronounced at the time of the bowing."  

سِوَى تَكْبِيرَتَىِ الرُّكُوعِ  

The Prophet of Allah ﷺ said: There are seven takers in the first rak'ah and five in the second rak'ah of the prayer offered on the day of the breaking of the fast.  

نَبِيُّ اللَّهِ ﷺ التَّكْبِيرُ فِي الْفِطْرِ سَبْعٌ فِي الأُولَى وَخَمْسٌ فِي الآخِرَةِ وَالْقِرَاءَةُ بَعْدَهُمَا كِلْتَيْهِمَا  

The Prophet ﷺ used to say on the day of the breaking of the fast seven takbirs in the first rak'ah and then recite the Qur'an, and utter the takbir (Allah is most great). Then he would stand, and utter the takbir four times. Thereafter he would recite the Qur'an and bow. Abu Dawud said: This has been narrated by Waki' and Ibn al-Mubarak. Their version goes: "Seven (in the first rak'ah) and five (in the second)."  

أَنَّ النَّبِيَّ ﷺ كَانَ يُكَبِّرُ فِي الْفِطْرِ فِي الأُولَى سَبْعًا ثُمَّ يَقْرَأُ ثُمَّ يُكَبِّرُ ثُمَّ يَقُومُ فَيُكَبِّرُ أَرْبَعًا ثُمَّ يَقْرَأُ ثُمَّ يَرْكَعُ  

Sa'id b. al-'As asked Abu Musa al-Ash'ari and Hudhaifah b. al-Yaman: How would the Messenger of Allah ﷺ utter the takbir (Allah is most great) in the prayer of the day of sacrifice and of the breaking of the fast. Abu Musa said: He uttered takbir four times as he did at funerals. Hudhaifah said: He is correct. Then Abu Musa said: I used to utter the takbir in a similar way when I was the governor of Basrah. Abu 'Aishah said: I was present there when Sa'id b. al-'As asked.  

أَنَّ سَعِيدَ بْنَ الْعَاصِ سَأَلَ أَبَا مُوسَى الأَشْعَرِيَّ وَحُذَيْفَةَ بْنَ الْيَمَانِ كَيْفَ كَانَ رَسُولُ اللَّهِ ﷺ يُكَبِّرُ فِي الأَضْحَى وَالْفِطْرِ فَقَالَ أَبُو مُوسَى كَانَ يُكَبِّرُ أَرْبَعًا تَكْبِيرَهُ عَلَى الْجَنَائِزِ فَقَالَ حُذَيْفَةُ صَدَقَ فَقَالَ أَبُو مُوسَى كَذَلِكَ كُنْتُ أُكَبِّرُ فِي الْبَصْرَةِ حَيْثُ كُنْتُ عَلَيْهِمْ وَقَالَ أَبُو عَائِشَةَ وَأَنَا حَاضِرٌ سَعِيدَ بْنَ الْعَاصِ