How to get the result with these time intervals in php

I'm using a time clock system which, by default, records only the employee's entry and exit times. I'm customizing it so that it's possible to also record break times but I'm having trouble getting the break time to be subtracted from the total time. This snippet of code is used to register the time between the check-in and check-out:

$time1 = Carbon::createFromFormat("Y-m-d H:i:s", $timeIN); 
$time2 = Carbon::createFromFormat("Y-m-d H:i:s", $timeOUT); 
$th = $time1->diffInHours($time2);
$tm = floor(($time1->diffInMinutes($time2) - (60 * $th)));
$totalhour = ($th.".".$tm);

The variable ($totalhour) receives the total value between the input register and the output register. It sends to the database in H.i format (hour.minutes), then another page searches for this information in the database and replaces the point (.) with (hr). Based on this code, I did the same to get the interval start and end timestamps. I was able to get the time between the start time and end time interval with the code below:

$breakstart = table::attendance()->where([['idno', $idno]])->value('breakstart');
$breakend = table::attendance()->where([['idno', $idno]])->value('breakend');
$one = Carbon::createFromFormat("H:i:s", $breakstart); 
$two = Carbon::createFromFormat("H:i:s", $breakend);
$breakone = $one->diffInHours($two);
$breaktwo = floor(($one->diffInMinutes($two) - (60 * $breakone)));
$totalbreak = $breakone.".".$breaktwo;

The $totalbreak variable stores the time taken between the start and end of the break. I was also successful in getting the time between this interval. Now, I need the total time to be done by subtracting the time obtained from the record at the beginning of the interval to the record at the end of the interval. I did with this code and got good result up to a point. Could you give me tips on how to get an assertive result in this case?

$totalhour = ($th.".".$tm) - ($totalbreak);

I tried to get the total time by subtracting the break time, but without success.

via Chebli Mohamed