Hi every one i have a problem i don't know File extension
because now i have 2 time = start and stop time in text label screen1
is 2 text is label5 = start and label 5_1 =stopand next screen

and next screen
i have 3 label
label6 = start , label6_1 = stop
label6 i use code label5.Text label6 show start time same screen1 and i use code stop time same start time

now i use code to total is Label6 - Label6_1 = Start time - Stop time
and is error and show The value '9.15.23' cannot be converted to a number.
i want to know how i convert to number or i calculate total time in screen1
if i will calculate total time in screen1 how i can do