You can rewrite the 16 as a fraction: 16/1
This works since 16/1 is still equal to 16.
(You can rewrite any whole number as a fraction over 1: [tex]number = \frac{number}{1}[/tex] )
Now just multiply the two fractions as normal:
[tex]\frac{1}{16} \times \frac{16}{1}[/tex] (Numerator times numerator, and denominator times denominator)
= [tex]\frac{16}{16}[/tex]
= 1
