summing all hours end of the month

[Guest]

hi
need little help here if somebody can show me the formula for total hours

sample
c1 12:30
c2 5:15
c3 4:25
c4 6:40
c6 then total hour
i just can't add it up i tryed please help thank's

 

[Ian]

=SUM(C1:C4) and format the cell as [h]:mm (note the square brackets)