The following story is told by my old high school English teacher who used to live in Vietnam:
“Ads in Vietnam puts items on sale for 88% of their original price. The 8th, 18th, and 28th of each month are lucky, and on those days, fake money is sold in the streets to be burned for luck. People get married on those dates. Some people even pay to have their phone numbers include the number 8 to gain respect from their customers.”
Analysis: These folklore practices in Vietnam are because they believe the number eight to be lucky in Vietnamese culture. This idea stems from the Vietnamese language much like the superstition about the number four. In Vietnamese, the word for the number eight is almost identical to the word for “develop.” Since development is viewed positively in Vietnamese culture, the number eight is celebrated. It is very interesting that although four is an unlucky number, 14 is not, whereas the number eight is a lucky number and so is 18 and 28. My old teacher learned of this lucky omen through his interactions with local Vietnamese people during his time in Da Nang, Vietnam and observations of everyday life.