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## Converting units of time

Current time:0:00Total duration:4:54

# Converting units: minutes to hours

CCSS Math: 5.MD.A.1

## Video transcript

How many hours are
in 549 minutes? And we can write it as
a decimal or a fraction. So essentially, we're
going to take 549 minutes and divide them
into groups of 60. Why 60? Because we know that one
hour is equal to 60 minutes. So it's essentially saying, how
many groups of 60 minutes can we divide 549 into. Or another way of
thinking about that is, well, what is 549
divided into groups of 60. This is how many hours
we're going to have. So let's do that. Let's take 549 and
divide it by 60. So let's see, 6 goes
into 54 9 times. So 60 is going to
go into 540 9 times. We're going to have a
little bit left over. So we have 9 times 60 is 540. We subtract. We have 9 left over. And now let's see, we
have a little left over, so we're going to get a decimal. So let's put a decimal
place right over here and let's throw
some 0's over there. Let's bring down a 0. So we bring down a 0. 60 goes into 90 1 time. 1 times 60 is 60. And we subtract. We get 30. Let's bring down another 0. And so we get to 300. 60 goes into 300 5 times. 5 times 60, 6 times 6 is
30, so 5 times 60 is 300. Subtract and we are done. So you divide 549
into groups of 60. You can divide it into
9.15 groups of 60 minutes. A group of 60
minutes is an hour. So this 549 minutes
is 9.15 hours. I want to make sure that we
can visualize that properly. So let's actually construct
what 9.15 hours looks like. So let me draw a little
line here, and on the top I'll label Hours, and on the
bottom I'll label Minutes. So this is 0 hours, 0 minutes. And now we have 1 hour,
which is 60 minutes. Now we have 2 hours,
which is 120 minutes. Then you have 3 hours,
which is 180 minutes. Then you have 4 hours,
which is 240 minutes. 5 hours is 300 minutes. 6 hours is 360 minutes. 7 hours, I might be running out
of space, is for 420 minutes. Let me copy and paste
this someplace where I have more real estate. So let me clear that. And then let me
paste that someplace where I don't run into
my other math that I did. All right. So then you have 8
hours is 480 minutes. And then you have 9 hours. Notice, I'm just adding
60 minutes every time. 9 hours is 540 minutes. Or another way you could
think about it is, well, if each hour is 60,
9 times 60 is 540. And we don't want
to go to just 540. We have another 9 left. So then we have to go another
9 minutes to go to 549. So you have 9 minutes left over. So another way of thinking about
this, is that 549 is 9 hours. And then you have 9
minutes left over. And 9 minutes is what
fraction of an hour? Well, 60 minutes
is a whole hour. So 9 minutes is 9/60 of an hour. So you could write it this way. It's 9 and 9/60 hours. Or we could write this as
an equivalent fraction. 9/60 is the same
thing if we divide the numerator and
the denominator by 3, is the same thing as 3/20. So we could write
this as 9 and 3/20. And 3/20, well we could figure
out what that is going to be. Let's see, 20 divided by 3. It's definitely
going to be smaller than 1, because 3
is smaller than 20. So let's throw some 0's on here. 20 doesn't go into 3, but
it does go into 30 1 time. 1 times 20 is 20. Subtract, we get a 10. Bring down a 0. 20 goes into 100 5 times. 5 times 20 is 100. And we are done. So notice, 3 over 20 is
the exact same thing. So 9 and 3/20 is the exact
same thing as 9 and 15/100. These are all
equivalent answers.