Reg a conditional column

Hi ,

I need to calculate the sum of efforts spend on each task for particular month , i have a column in my excel sheet as Actual hours and Actual hours1 ,Actual hours2.

For example , If the task is started on January month and ended in Febrauary month ,then the Actual efforts are splitted as Actual hour1 for january and Actual hour2 for February. So if i need to calculate the January month effort it should calculate as Actual Hour (Jan)+ Actual Hour 1.

That is 104 hours for January

For February its should be Actual hour ( Feb )+ Actual Hour2 =44

Could ypu please help to insert a conditional column as above to create the dash board