1st confusion 您好，我想换800元现金还信用卡. 换人民币还是换美元？ ……。 The sentence confuses me. It doesn't make sense: I want to change 800 yuan cash also credit card. My best guess is that someone wants to put 800 cash on their credit card? What is the correct translation? the translation is : I want to exchange 800yuan, Cash, for paying back my credit card. should I change RMB or US dollar? this sentence is very confusing. maybe you should ask again, what this person really wants to say. 2nd confusion How do I write down 10020? 一千00二十 or 一千0二十。 So basically 1 or 2 times a 0? 1 time 0. should be 一万 ，not 一千

hello.about the 1st your guess is right.“还” has two different pronunciations.“hái” and “huán”. the Second means return something. In Chinese 10 thousand is not 10千, is 万.Chinese has a character can definite this magnitude.so 10020 is 一万零二十. next is from 万(10000) to 千万 (10000*10^3),10^8 is 亿.10^8*10^3 is 千亿.it enough for simple calculation.

1st.your guess is correct

2nd.一万零二十

1. The sentence makes no sense. Most probably you left out some crucial words. What I guess is that it is a credit card cash advance for 800RMB. 2. You can say 一万二十. Using 零 is more formal to make sure that there is no mistake on the amount made.