Belief in Allah and Tawhid (Monotheism)
Belief in His Angels
Belief in His Books
Belief in His Messengers
Belief in the Last Day
Belief in Divine Preordainment and Divine Decrees (Qadhaa’ and Qadar)

Aqidah defines a Muslim, and teaching your kids, at least, the basics of Iman and Islamic studies for kids can deeply instill the love of Islam in their little hearts and make them strongly adhere to the religion. Also, prophet Muhammad PBUH said: “If Allah wants to do good to a person, He makes him comprehend the religion. (Sahih Al-Bukhari)