To determine which number is less than −1.5, we first convert all the numbers into decimal form:
- −1 2/3 = −1 - 0.666... = −1.666...
- −1 1/3 = −1 - 0.333... = −1.333...
- −1.5 = −1.5
- −1 = −1
Now we compare these decimal values with −1.5:
- −1 2/3 (−1.666...) is less than −1.5.
- −1 1/3 (−1.333...) is greater than −1.5.
- −1.5 is equal to −1.5.
- −1 (−1) is greater than −1.5.
The only number that is less than −1.5 is −1 2/3.
So, the answer is −1 2/3.