Anas (May Allah be pleased with him) reported that he passed by some children and greeted them. Then he said:
"Messenger of Allah ﷺ used to do the same."

[Al-Bukhari and Muslim].

عن أنس رضي الله عنه أنه مر على صبيان، فسلم عليهم، وقال: كان رسول الله ﷺ يفعله” ((متفق عليه))