Through these exercises, students will acquire the technic called ‘falsification’. By trying to falsify a formula, one can tell whether it’s a tautology or not. Similarly, one can also tell whether it’s contradiction or not by trying to satisfying the formula.

Common Mistakes:

- Before falsifying a formula, you need to figure out how the formula is formed and by which order the logical connectives are processed.
- If you assume A\equiv B to be true, don’t forget to discuss two possibilities: A and B are both true or are both false. If you are assuming A\equiv B to be false, you might have the same issue.