The area covered by water lilies doubles every day. In 27 days, water lilies will cover half the pond. By the 28th day, the area will double, so it will take 27 days for water lilies to cover half the pond.

Tips for learning mathematics

1, you should be good at thinking when learning mathematics, and the answers you come up with are far more impressive than those others say.

2. Prepare well before class, so that we can better digest and absorb the unknown knowledge points in math class.

3, the mathematical formula must be memorized, and it must be deduced and can be deduced.

4. The most basic thing to learn mathematics well is to master the knowledge points of textbooks and exercises after class.