How do you write 0.045 as a reduced fraction

0.045 = 45/1000

Divide top and bottom by their greatest common factor.
It looks to me as though the greatest common factor of  45  and  1,000  is  5 .
Divide top and bottom by  5  and we have  9/200 .  That's the simplest form.

 0.045=45/1000

Imagine trying to reach the value 1.000

At 0.045, you'd only be 45/1000 of the way to 1.000