Question 485802
<pre>

Scientific notation has the form:

{{{(A_number_between_1_and 10_inclusive_of_1_and_exclusive_of_10)}}}{{{"×"}}}{{{10^((integer_exponent))}}}

(4.4×10<sup>-19</sup>)(7.7×10<sup>-1</sup>)

Multiply the 4.4 by the 7.7 getting 33.88
Add the exponents of 10, (-19)+(-1) getting -20

That gives 

33.88×10<sup>-20</sup>

but that is not in scientific notation because
33.88 is not between 1 and 10.  So we write it 
in scientific notation as 3.388×10<sup>1</sup> and substitute
that for 33.88:

(3.388×10<sup>1</sup>)×10<sup>-20</sup>

3.388×10<sup>1</sup>×10<sup>-20</sup>

finally add the exponents of 10, (1)+(-20) getting -19 

3.388×10<sup>-19</sup>

Edwin</pre>