"Ichi" (一). Or, if you're referring to one object, "hitotsu" (一つ).
Hyaku.
shimobe is one of the words for servant
"Chakumoku" is one way to say it.
gakuen is one way to say it
if you mean the one you wash with its suponji
Sen is one thousand in Japanese.
Shi or yon. (Shi when counting from one to ten, yon thereafter.)
i think its wata although that may just be one reading of its kanji
"Kouzui" is one way to say "flood." It is pronounced: KOH-zooey
"Ichi" Would be the translation for one, meaning First or One as a number. pronouched EE-chi
Sekai improvment: that's right the one above but the character is 世界
Musuko: one's own son. Musukosan: someone else's son.