Verified Answer :

RhysH

604+406.64=1010.64
604-406.64=197.36
1010.64-197.36=813.28

813.28 is the difference

eah

\(604+406,64=1010,64 \ \ \ \ \ \ \ \rightarrow their \ sum \\ 604-406,64=197,36 \ \ \ \ \ \ \ \ \ \rightarrow their \ difference \\ 1010,64-197.36=\boxed{813,28} \ \ \ \ \ \ \ \ \leftarrow ANSWER\)