Question 1104693
8 hours minus 4 hours 20 minutes 35 seconds


Borrowing will be necessary for the subtraction of the minutes and the seconds.


60 minutes per hour;
60 seconds per minute;


7+60/60 gives you the 8 hours as hours and minutes;


7+59/60+60/60 gives you the 8 hours as hours minutes seconds


{{{7*hour+59*minutes+60*seconds-(4*hour+20*minutes+35*seconds)}}}
{{{3*hour+(59-20)minutes+(60-35)*seconds}}}
{{{4*hours+39*minutes+25*seconds}}}


4 hours 39 minutes 25 seconds