To write 1.5 as a fraction, we can use the following steps:

1. Write 1.5 as a fraction with a denominator of 1: 1.5/1
2. Count the number of digits after the decimal point, which is 1 in this case.
3. Multiply both the numerator and denominator by 10 to the power of the number of digits after the decimal point. In this case, we multiply by 10.
4. Simplify the resulting fraction if possible.

Using these steps, we get:

1.5/1 = 15/10

We can simplify this fraction by dividing both the numerator and denominator by their greatest common factor, which is 5:

15/10 = (15 ÷ 5) / (10 ÷ 5) = 3/2

Therefore, 1.5 as a fraction is 3/2.