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# Time differences example

CCSS.Math:

## Video transcript

we are asked how much time has passed from the time on the left so right over here to the time on the right which we see right over here and they say that the time passed is less than 12 hours so like always pause this video and see if you can answer that on your own before we work on this together all right so first I just want to figure out what time is being told by each of these clock faces so let's go here on the left so the first thing I'm going to do is look at the hour hand and we can see that the hour hand has gone a little bit past 6 so it's going to be 6 something 6 something and then to figure out what the minutes are I can look at the minute hand right over here and say well how far has it gone in minutes and I like to count by fives because we know when we go from 12 on the clock to one that actually one two three four five minutes have gone by in fact between any two numbers it's five minutes so we go 5 10 15 20 25 30 35 40 and then 41 42 43 that's where it's pointing so it's 6 43 is where we're starting and then where we're ending let's see the hour hand is a little bit past 9 you can see it's past 9 and so it's not to say what its closest to its what its past so even if the hour hand was like there even if it was closer to 10 but not quite at 10 you would say okay it's gonna be 9 something it's past 9 and so and only if it got to 10 or past 10 then you would say it's 10 something so this is going to be 9 something and to figure out what that something is once again we start here we can count by fives 5 minutes 10 minutes and then we got we have one more we get to 11 minutes so it's 911 and they tell us that this is less than 12 hours apart so it's not like 643 in one day it may be at night and then 911 the next morning this is maybe the same morning or the same evening and so we can set up a line here so let's set up a time line and so let's see we the six six is the sixth hour is going to be important so that's six o'clock and let's see maybe we want to go all the way to ten o'clock so that we go beyond nine eleven and so then we could say let's go up to seven eight and nine if we get my spacing right so let's say that this is seven o'clock right over here this is eight o'clock right over there and then that is nine o'clock right over there it's not going to be a perfect drawing but this is pretty close and so let's see we are starting at 643 which is going to be let's see it's going to be roughly and I just have to say roughly it's going to be right over there that's where we are starting and then nine eleven is going to be roughly right over there so that is when we are ending so how much time has gone by well to go from 643 to seven o'clock how many minutes is that well to go from forty-three minutes to 60 minutes you have to add 17 minutes so this right over here that is 17 minutes I'll just write it out and then we can see we have another two hours that goes by from 7 o'clock to 9 o'clock so then that's 2 hours and then to go from 9 o'clock to 9 11 what is going on well that's going to be another 11 minutes 11 minutes so how much time is happen it's going to be 17 minutes plus 2 hours plus 11 minutes well I find it a little bit easier to just think about the minutes first so if I had 17 minutes to 11 minutes 17 plus 11 is 28 I can do that on the side if you want to see it 7 plus 1 is 8 1 plus 1 is 2 so we are going to have a total of 2 hours and 28 minutes and I could write it that way 2 hours 2 hours and 28 minutes and we are done