3. We know that $0,1,2,3, \cdots \cdots$ are called natural numbers, and natural numbers greater than 1 that can only be divided by 1 and themselves are called prime numbers, such as 2, $3,5,7,11$, etc. In ascending order, the 8th prime number is $\qquad$.
【Key Point】Prime and Composite Numbers 【Difficulty】Trick to Remember
【Answer】19
【Analysis】In ascending order, $2, 3, 5, 7, 11, 13, 17, 19 \cdots \cdots$.