Arithmetic Grade Six

Lesson Thirty-four: Subtracting Hours and Minutes

When you subtract hours and minutes, you subtract the hours and minutes separately. Here's an example: 


	  3:42
	- 2:12
	-------
	  1:30
This problem breaks down into two subtraction problems: 3-2=1 and 42-12=30.

Here are three other ways this problem could have been written: 


  1)	  3 hours, 42 minutes
	- 2 hours, 12 minutes
	---------------------
	  5 hours, 54 minutes

  2)	3 hours, 42 minutes - 2 hours, 12 minutes = 5 hours, 54 minutes

  3)	3:42 - 2:12 = 5:54
Additionally, we could use the abbreviations for hours and minutes: 

  1)	  3 hrs, 42 mins
	- 2 hrs, 12 mins
	---------------------
	  5 hrs, 54 mins

  2)	3 hrs, 42 mins - 2 hrs, 12 mins = 5 hrs, 54 mins
Here's another example: 

	2:33 - 1:22 = 1:11
Remember, if your minutes come out to less than ten, you still need to fill in a zero like this: 

	2:33 - 1:27 = 1:06
It would be incorrect to write this answer like this: 1:6.

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