Express 0.64 as a fraction in lowest term?
a. 64/10
b.5/32
c.4/5
d.16/25

In its decimal form, it says  ' 64 / 100 '.

In order to change it to its lowest terms, we look to see whether the
numerator and denominator have a common factor greater than ' 1 '. 
If they do, then we can divide numerator and denominator by their
common factor, and have the same fraction in lower terms.

The common factors of  64  and  100  are  1,  2, and  4 .
We could divide top and bottom by 2, but that wouldn't finish the job. 
It's always best to divide them by their greatest common factor, and
once you do that, you're done.

Dividing the numerator and denominator both by  4,
we get the fraction in its lowest terms:

         0.64  =  64/100  =  16/25