Answer:
6739/100 
Explanation:
heres how i got that answer
first step 
any expression raised to the power of 1 equals its self. remove unnecessary parentheses 
(6.83 x 10) - 9.1 x 10^-1
second step
 6.83 x 10 = 68.3 then make the other decimal into a fraction so 91 over 10 or 91/10 any expression raised to the power of - 1 equals its reciprocal so now you have 
68.3 - 91/10 x 1/10
third step 
convert the decimal into a fraction 683/10
then multiple 91/10 and 1/10 to get 91/100
so now you should have 683/10 - 91/100
last step 
subtract the fractions giving you 
6739 over 100