[Culture] Tiền lì xì
The sentence in Duolingo:
Tiền lì xì
I dug a bit into it, and here is the background I found.
On Tết Nguyên Đán (Lunar New Year), a common gift for children is tiền lì xì. It is comprised of a chiếc phong bì nhỏ (small envelope) with a trang trí màu vàng (gold trim).
This practice has an associated myth: Somewhere there was a huge peach blossom tree, containing evil spirits. Normally these spirits were trapped there, guarded by the gods. However, when the gods left to celebrate new years, a particular spirit named Tuy would escape. He would rub the heads of children, causing them to cry and break into fever. One day some gods disguised themselves as coins in red cloth. Some parents put these coins under their children's pillows. These coins scared away Tuy. From that point forward, word spread and the custom continued to keep Tuy away.
Some further notes on the practice: the envelope itself shields the gift to prevent comparison; the red color of the envelope signifies prosperity and luck. This is part of a larger sequence of events, starting with family visiting grandparents to bring gifts - the tiền lì xì is then given from the grandparents and other adults to the children.
How much to give? As with any gift given, I suspect this is more an art to learn over time and subject to local conditions. An article (linked below) provides some suggestions:
While many suggest VND10,000-VND20,000 for kids of casual acquaintances, like neighbors, others say VND20,000, or around 1 US dollar, should be the average for kids under 10 years old and VND50,000 for older ones.
For children in the family or of close friends, VND50,000-100,000 is apparently considered the norm these days.