30件
ばんごう
number
ひとつ
one (used when counting things in general)
ひとり、ふたり、〜にん
one person, two people, - people
ひゃく
hundred
ふたつ
two (used when counting things in general)
みっつ
three (used when counting things in general)
むっつ
six (used when counting things in general)
やっつ
eight (used when counting things in general)
よっつ
four (used when counting things in general)
ろく
six