16. Line $a$ is parallel to line $b$, and there are 5 points and 6 points on lines $a$ and $b$ respectively. Using these points as vertices, $\qquad$ different triangles can be drawn.
Analysis: The key point is the principle of addition and multiplication or permutations and combinations.
This type of question requires students to master the principle of addition and multiplication.

To form a triangle, three points are needed, but the order of selecting these three points does not matter.
To form such a triangle, one can choose one point or two points from $a$:
First case: Choose one point from $a$, there are 5 ways to choose;
Choose two points from $b$, using the method of counting line segments, there are $6 \times 5 \div 2=15$ ways to choose
There are a total of $5 \times 15=75$ ways to choose;

Second case: Choose two points from $a$, using the method of counting line segments, there are $5 \times 4 \div 2=10$ ways to choose;
Choose one point from $b$, there are 6 ways to choose
There are a total of $10 \times 6=60$ ways to choose;

Therefore, a total of $75+60=135$ ways to construct.