Answer
$3.4\times10^{5}$
Work Step by Step
We start with the given expression: $0.5(6.8\times10^{5})$
We rewrite the expression using the associative property: $0.5\times6.8\times10^{5}$
We multiply the first two terms: $3.4\times10^{5}$
Since 3.4 is between 1 and 10 and 5 is an integer, the number is in scientific notation.