Video Transcript
Hours and Minutes
In this video, we will learn how to
identify the number of minutes in an hour and how to convert between hours and
minutes using models. To help us convert between minutes
and hours, we need to know how many minutes there are in one hour. Let’s count them. Each number on the clock represents
five minutes. Let’s count around the clock in
fives. Five, 10, 15, 20, 25, 30, 35, 40,
45, 50, 55, 60. There are 60 minutes in one
hour.
If one hour equals 60 minutes, how
many minutes are there in half an hour? What is half of 60? We know that half of six is
three. So half of 60 is 30. How many minutes are there in a
quarter of an hour? We know that half an hour is 30
minutes and there are two-quarters in a half hour. So we need to halve 30. There are 15 minutes in a quarter
hour. There are four quarter hours in an
hour. Each quarter of an hour is worth 15
minutes.
If quarter of an hour is worth 15
minutes, then three-quarters of an hour will be worth 45 minutes and one-third of an
hour is worth 20 minutes. If there are 60 minutes in one
hour, how many minutes would that be in two hours? What is 60 plus 60 or double
60? We know that double six is 12;
double 60 is 120. If there are 60 minutes in one
hour, there are 120 minutes in two hours. We’ve learned that there are 60
minutes in one hour. Let’s use this fact to help us
answer some questions, where we’re asked to convert from minutes to hours or hours
to minutes.
One hour and 30 minutes is what
minutes. Think: How many minutes are in one
hour?
In this question, we’re shown a
part–whole model. The whole amount is one hour and 30
minutes. We know that the first part is one
hour and the second part is 30 minutes. In this question, we have to work
out how many minutes there are in one hour and 30 minutes. We’re only given one of the parts
in the part–whole model, the 30 minutes.
To work out how many minutes are in
the other part, we need to think about how many minutes there are in an hour. There are 60 minutes in one
hour. Five, 10, 15, 20, 25, 30, 35, 40,
45, 50, 55, 60. Now, what we need to do is add
together the two parts, 60 and 30. We know that six plus three is nine
and six 10s plus three 10s is nine 10s. Nine 10s are 90. 60 plus 30 is 90. One hour and 30 minutes is 90
minutes.
65 minutes is one hour and what
minutes. Think: How many minutes are in one
hour?
We’re shown a part–whole model. We know the whole amount is 65
minutes. We know that one of the parts is an
hour. And we need to work out what the
second part is worth. We’re told to think about how many
minutes there are in one hour. There are 60 minutes in one
hour. Now, we can find the missing
part. It’s the difference between 60 and
65.
In other words, we need to subtract
60 from 65. Five ones take away no ones leaves
us with five ones. And six take away six is
nothing. So 65 take away 60 equals five. 65 minutes is one hour and five
minutes. 60 plus five makes 65. The missing amount is five
minutes. We know that one hour is 60
minutes. So 65 minutes is one hour and five
minutes.
Fill in the blank: Two hours and 10
minutes equals what minutes.
In this question, we have to work
out how many minutes there are in two hours and 10 minutes. We could use a part–whole
model. We know the whole amount is two
hours, 10 minutes. We could break this amount apart
into two hours and 10 minutes. We know that this part is worth 10
minutes. How many minutes are there in two
hours?
So if one hour is 60 minutes, two
hours is double 60. We know that six plus six is 12, so
60 plus 60 is 120. Now, we just need to add together
the two parts. What is 120 plus 10? It’s 130. Two hours and 10 minutes equals 130
minutes.
What is two and a half hours in
minutes?
We could use a bar model to help us
think about this problem. The whole amount is two and a half
hours. Each of these parts is an hour, so
there were two hours. And this part represents half an
hour. We know there are 60 minutes in one
hour.
So to find the number of minutes in
two hours, we need to double 60. Double six is 12; double 60 is
120. And we know that half of 60 is
30. So to find the total number of
minutes in two and a half hours, we need to add together 120 and 30. Two and a half hours in minutes is
150 minutes.
70 minutes is one hour and 10
minutes. 80 minutes is one hour and what
minutes.
We know that one hour is worth 60
minutes. So 70 minutes is 60 plus 10 or one
hour and 10 minutes. If 60 minutes is worth an hour,
then 80 minutes can be partitioned into one hour or 60 minutes and 20 minutes. We know that 60 plus 20 equals
80. If 70 minutes is one hour and 10
minutes, 80 minutes is one hour and 20 minutes. The missing number is 20.
What have we learned in this
video? We’ve learned how to identify the
number of minutes in an hour and how to convert between hours and minutes using bar
models and part–whole models.
