Why do astronomers need math?

If one astronomer counts 2,497 stars this week, then he gets sick and another astronomer has to take over his job, and the second astronomer counts 1,762 stars the next week, somebody has to be able to figure out how many stars got counted all together, between the two astronomers.

If there is no supercomputer available, they have to call in somebody who has a pencil, and knows how to use it.