وَالْقِسْمُ الْأَوَّلُ إِنَّمَا يَتْبَعُ مَتْبُوعَهُ فِي عَشَرَةِ أَشْيَاءَ: فِي الْإِعْرَابِ وَالتَّعْرِيفِ وَالتَّنْكِيرِ وَالْإِفْرَادِ وَالتَّثْنِيَةِ وَالْجَمْعِ وَالتَّذْكِيرِ وَالتَّأْنِيثِ.
Translation: The first type, direct naʿt, follows its noun in ten features: nominative, accusative, genitive; definite, indefinite; singular, dual, plural; masculine, feminine.
The count is 3 + 2 + 3 + 2 = 10. “Case” is a single category but covers three cases; number covers three possibilities. The ten-count is complete.