The moving average is calculated based on historical prices and is a backward indicator,Unable to forcast future prices. But the moving average still represents the price trend, so we can forcast by moving average. Each point of the 20-day SMA is calculated based on the closing price of the past 20 days. Therefore, we can know that the closing price of the first 20 days directly affects the latest point of SMA. The last 20 days are the prices included in the calculation, which directly affect the trend of the latest points. For example,if the day before the 20th is a sharp fall, the latest SMA becomes an upward trend;If the day before the 20th is a sharp rise, the latest SMA becomes a downward trend,it showing the opposite trend