訓 かず,かぞ(える) ・ 音 スウ,ス
Sino-Vietnamese: số
攵 (a hand holding a stick) on the right for meaning, the left side for sound: tapping out a tally. Number, to count — 数学 mathematics.
Stroke data: KanjiVG (CC BY-SA 3.0) — kanjivg.tagaini.net
学生の数を数えます。 (がくせいのかずをかぞえます)
I will count the number of students.