New Sum of Client Hours

Let
(
[
_client1 = If ( Client Module 1 = "1" ; Client Hours 1 );
_client2 = If ( Client Module 2 = "1" ; Client Hours 2 );
_client3 = If ( Client Module 3 = "1" ; Client Hours 3 );
_client4 = If ( Client Module 4 = "1" ; Client Hours 4 );
_client5 = If ( Client Module 5 = "1" ; Client Hours 5 );
_client6 = If ( Client Module 6 = "1" ; Client Hours 6 );
_client7 = If ( Client Module 7 = "1" ; Client Hours 7 );
_client8 = If ( Client Module 8 = "1" ; Client Hours 8 )
] ;
Sum ( _client1 ; _client2 ; _client3 ; _client4 ; _client5 ; _client6 ; _client7 ; _client8 )
)