#### Answer

$1$

#### Work Step by Step

RECALL:
$\log_b{x}=y \longrightarrow b^y=x$
Let
$\log_b{b} = y$
Use the rule above to obtain:
$\log_b{b}=y \longrightarrow b^y=b$
Use the rule $a^m=a^n \longrightarrow m=n$ to obtain:
$b^y=b^1 \longrightarrow y = 1$
Thus, the missing expression in the given statement is: $1$