"Four hundred yuan"
Do you mean by accepting pinyin as a correct answer? In my opinion, this would be the counterproductive option, because then people would care about memorizing the pinyin but not the actual word (the character) so much.
But anyways, if you install the Chinese keyboard, you just have to type in pinyin and the hanzi appears magically (text prediction, you have to choose the correct one sometimes). It's actually quite easy to use the Chinese keyboard.
The Microsoft Pinyin keyboard is good enough.