Answer
$.0052$
Work Step by Step
RECALL:
(i) Scientific notation has the form $a(10^n)$, where $1 \le a \lt 10$ and where $n$ is an integer.
(ii) $a^m \cdot a^n = a^{m+n}$
Write each factor in scientific notation to obtain:
$=4(10^{-4}) \cdot (1.3)(10^1)$
Multiply $4$ and $1.3$ together, and the powers of 10 together to obtain:
$=5.2(10^{-4+1})
\\=5.2(10^{-3})\\\\=.0052$
