What is the answer to 30-9?

To find the solution to the expression 30 - 9, you need to perform a simple subtraction. Starting with 30, subtracting 9 means you are taking away 9 from 30.

When you execute this operation:

30 - 9 = 21

This indicates that if you take away 9 from 30, 21 remains. Thus, the correct answer is 21. Understanding basic subtraction is fundamental in arithmetic, and being able to perform these operations accurately is crucial, especially in situations that may arise in firefighting where quick calculations are necessary for safety and efficiency.