The couple who returned 65,700 yuan (S$13,400) to a money changer at People's Park Complex were in Singapore to visit their daughter during the school holidays.
They were exchanging such a large amount of money for her school fees, psychology lecturer Zhang Yitian told The Sunday Times over the phone from China yesterday.
His only child, 18-year-old Zhang Jiasi, currently studies at Hua Yi Secondary School and was recently accepted into the Cambridge School of Visual and Performing Arts in Britain. The acceptance was conditional on her having $60,000 in a local bank account.
A week ago, Mr Zhang and his wife Cheng Qi, both 46, returned an extra $13,400 to Crante Money Changer after a money changer mistakenly keyed in the wrong figure.
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The couple had asked to exchange 207,300 yuan to Singapore dollars, but the money changer keyed in 273,000 yuan and gave them $55,600, Shin Min Daily News reported last Friday.
After news broke about their action, netizens praised them for their honesty.
The couple, who are from China's northern Hebei province, returned home last Wednesday.
On their good deed, Mr Zhang said in Mandarin: "I didn't expect it to get so much attention. Last night, my daughter told us many people talked about it, but my wife and I don't understand English."
"I know many countries don't have a good image of mainland Chinese," he added. "It's my own country - I understand. There are many of my countrymen who can lack civility, but I still believe there are many more people - not just Chinese - who are kind."
He said that most Singaporeans are friendly to them, and his family likes the country very much.
Asked about the stereotypical view of mainland Chinese that some Singaporeans may still have, Mr Zhang said: "Everyone has his own perspective and ways of thinking - there is no right or wrong. I will respect their views, but it does not mean I agree with them."
His daughter, who lives with her aunt here, has been in Singapore for five years. Ms Zhang told The Sunday Times that she was very proud of her parents.
"They have always been my role models," she said.