What is 19 h 2 min 4 sec minus 16 h 4 min 52 sec?

Answer 1

19 02 04

16 04 52

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02 57 12

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52 seconds of the second time cannot be subtracted from 4 seconds of the first time, so borrow 1 minute from the 2 minutes of the first time. Now you have 64 seconds in the first time from which you can subtract 52 seconds in the second time giving you 12 seconds. After the borrow you did above there is only 1 minutes left in the first time and you cannot subtract 4 minutes of the second time from it. So borrow 1 hour from the first time, now the first time has 60 + 1 = 61 minutes. If you subtract 4 minutes of the second time, you get 57 minutes. Since you borrowed 1 hour from 19 hours in the first time, only 18 hours remain from which you can readily subtract 16 hours of the second time giving you 2 hours. Tracing back the result is 2 hours, 57 minute, 12 seconds. The subtraction is same as you would with decimal numbers, but when you borrow you have to remember that you borrow 60 units. I have included leading zeros in front of some numbers just to align them (limitations of the editor we use)