The most commonly referred and memorized juz' is "juz' Amma'," which is the 30th juz' and contains Surahs 78 through 114, most of the shortest suras in the Qur'an. 'Amma is generally taught first to children. Juz Amma is named after the 1st word of the 1st sura (i.e. sura 78) in that juz.
