To express the ratio of 64 to 8 as a fraction, you write it as:
\[ \frac{64}{8} \]
Next, simplify the fraction by dividing both the numerator and the denominator by their greatest common divisor (GCD). The GCD of 64 and 8 is 8.
Now, divide both by 8:
\[ \frac{64 \div 8}{8 \div 8} = \frac{8}{1} \]
So, the ratio of 64 to 8 in simplest form is:
\[ \frac{8}{1} \]
Or simply, 8:1.