#### Answer

$\frac{1}{4}$

#### Work Step by Step

Remember, that the product of a number $a$ and its reciprocal is 1. Therefore, the reciprocal of $a$ must be $\frac{1}{a}$ (which is just $a$ flipped), so that $a\times\frac{1}{a}=1$.
Therefore, the reciprocal of 4 is $\frac{1}{4}$.
$4\times\frac{1}{4}=1$