Chinese uses
两 (liǎng), not
二 (èr), before measure-style numerals like
万 (wàn, ten thousand) and
亿 (yì, hundred million). So 'two hundred million' is
两亿 (liǎngyì), not *
二亿. The same rule:
两万 (20,000),
两千 (2,000),
两百 (200) — but for plain digit-position counting like reading a phone number,
二 is used.