To determine which numbers are less than \(-1.5\), we can compare each of the given numbers:
- \(-1 \frac{1}{3}\) (which is \(-1.333...\)): This is greater than \(-1.5\).
- \(-1 \frac{2}{3}\) (which is \(-1.666...\)): This is less than \(-1.5\).
- \(-1.5\): This is equal to \(-1.5\).
- \(-1\): This is greater than \(-1.5\).
Therefore, the number less than \(-1.5\) is \(-1 \frac{2}{3}\) (or \(-1.666...\)).
To summarize:
- \(-1 \frac{1}{3}\) > \(-1.5\)
- \(-1 \frac{2}{3}\) < \(-1.5\) (this is the correct answer)
- \(-1.5\) = \(-1.5\)
- \(-1\) > \(-1.5\)
So, the answer is \(-1 \frac{2}{3}\).