Many people argue: 'Approximately' or 'approximately'?

Although it is a familiar phrase, often used in daily life, when asked, many people wonder and are confused about whether "sap si" - "xap si" is the correct spelling.

In Vietnamese, this word means almost equal, just a little bit different, often used to compare things, events, and people with each other.

So what do you think is the correct word? Leave your answer in the comment box below.