Kathir bin ‘Abdullah bin ‘Amr bin ‘Awf narrated, from his father, from his grandfather, that the Messenger of Allah ﷺ said the Takbir in the ‘Eid prayers, seven times in the first Rak’ah and five times in the second. (Using translation from Ibn Mājah 1279)
أَنَّ رَسُولَ اللهِ ﷺ كَانَ يُكَبِّرُ فِي الْعِيدَيْنِ سَبْعًا فِي الرَّكْعَةِ الْأُولَى وَخَمْسًا فِي الْآخِرَةِ سِوَى تَكْبِيرَتَيِ الرُّكُوعِ