First format A1 thru A3 as:

Custom hh:mm:ss.000

in A1 enter:
00:01:20.009
in A2 enter:
00:00:30.004
in A3 enter:
=A1+A2
and you will see:

00:01:50.013

just remember to enter the leading hours and minutes, even if they are zero!!
--
Gary''s Student - gsnu200838


"happythong" wrote:

i don't know how to add time in mini second
eg. 1min 20 sec 09 mini sec plus 30sec 04mini sec.