8 hours 5 minutes.
You can convert the 5 hours to minutes, and then subtract. Or if, as is more likely, you want the answer to be in hours and minutes, you do the following: you "borrow" one hour, and convert it into minutes. In other words, 5 hours is the same as 4 hours and 60 minutes. From there, you can easily subtract 15 minutes.
First, you can convert the 8 hours to 7 hours and 60 minutes. Then it's easy to subtract minutes from minutes.
2 hours 36 minutes 75 seconds.
When you subtract (for example) 31 - 15, you have to "borrow" from the ten's place, converting 31 (which is 3 tens and 1 unit) to 2 tens and 11 units. Similarly, when subtracting times, you convert (in this case) the 3 hours to 2 hours and 60 minutes (you convert one of the hours to the equivalent of 60 minutes). Now you can subtract hours minus hours, and minutes minus minutes.
8 hours 5 minutes.
7 hours 45 minutes.
You can convert the 5 hours to minutes, and then subtract. Or if, as is more likely, you want the answer to be in hours and minutes, you do the following: you "borrow" one hour, and convert it into minutes. In other words, 5 hours is the same as 4 hours and 60 minutes. From there, you can easily subtract 15 minutes.
First, you can convert the 8 hours to 7 hours and 60 minutes. Then it's easy to subtract minutes from minutes.
You can subtract the hours and the minutes separately.
The easiest way is to subtract 4 hours and add 5 minutes, getting 3 hours, 20 minutes.
59 minutes 53 seconds
2 hours 36 minutes 75 seconds.
Negative 0.297 minute (negative 17.82 seconds) is.
134 - 87 = 47 minutes
1 hr 25 mins.
Convert everything to a common unit (I suggest to convert to hours in this case, but minutes will do, too), then you can subtract.