get TOTAL of all textbox enteries in a single textbox

Question

i  created a windows c#  form with 10 text boxes all od which are numerical, once submit button it clicked it inserts into a sql database which works fine

 

I would like to create another text box name total, once any value entered in the 10 textbox it should appear in the total text box , if multiple textboxes are updated it should add example txtbox1 = 2, textbox = 3, textbox = 4

the total text box should = 9  . 

 

 

 

 

I aso created a SSRS REPORT and would like to create a button once clicked it should show the report, or once clicked a sql statement will execute and show results in PDF format eith way would work

 

please advise