【Analysis】First, find the pattern for the number of small stars in the $n$th figure, and use the pattern to further solve the problem.
【Solution】Solution: When $n=1$, there are $1 \times 2=2$ small stars;
When $n=2$, there are $2 \times(2+1)=6$ small stars;
When $n=3$, there are $3 \times(3+1)=12$ small stars;
$$
\cdots \text {; }
$$

The $n$th figure has $n(n+1)$ small stars;
So when $n=10$, there are $10 \times(10+1)=110$ small stars.
Therefore, the answer is: 110.
【Comment】Based on the characteristics of the numbers and the figures, identify the pattern contained in the problem, find the pattern, and use the pattern to solve the problem.
3. (5 points) As shown in the figure, when $n=1$, there are 2 small stars; when $n=2$, there are 6 small stars; when $n=3$, there are 12 small stars; $\cdots$; then when $n=10$, there are $\qquad$ small stars.