programmers run into a lot of errors
- it is expected so we need to know how to solve
Types of errors:
- logic errors:
  - mistake in algorithm that causes unexpected output
- syntax errors:
  - typo in code (doesn't follow rule in language)
  - forget to add ("",:{}, etc)
- run-time error
  - makes a program fail while running
  - aka bug
  - runs initially, but can't complete process
  - ex. dividing by 0
- overflow error
  - when program is required to calculate something that is outside of range of values.