Did you know that days can have color? A red letter day usually means a happy day. Blue Mondays may be sad days. Black usually means something bad. October 19, 1987, is called Black Monday. The stock market fell. When this happened, stocks lost a lot of their value all at once. People and businesses lost money. Because businesses lost money, they couldn't afford to pay all their workers. Many people lost their jobs. This happened all over the world.
Stocks are shares of companies. People can buy stocks. They can own a part of large companies. Stock prices go up and down. People make money when the stock prices go up. People lose money when the stock prices go down.