Numeral
いちおく
コウイチは東京に一億円のマンションを持っています。
Koichi has a one-hundred-million yen condo in Tokyo.
日本という小さな島国に一億もの人が住んでいることがしんじられない。
I can't believe that Japan, a tiny island country, has one hundred million people living on it.
宝くじで一億ドル当たったけど、私は既に兆万長者なので全部慈善活動に寄付したよ。
I won a hundred million dollars in the lottery, but I donated it all to charity because I’m a trillionaire.
One hundred million is one hundred million. That's a lot of zeros.
This is a jukugo word, which usually means on'yomi readings from the kanji. If you know the readings of your kanji you'll know how to read this as well.