Video Transcript
Look at the clock. Find the missing numbers to
tell the time in different ways. It is 55 minutes after
what. It is five minutes before
what. Pick the clock that shows the
same time.
To begin with, we’re given a
digital clock and told to look at it. What time does it say? 9:55. Now, how do we read a digital
time like 9:55? What do the numbers mean? The digit or digits that come
before the two dots show the number of hours that have gone by. In this case, it’s 9
something. And the two digits that come
after the dots show the number of minutes that have gone by. In this case, it’s 9:55. Now, we can describe the time
9:55 in different ways. And we need to find the missing
numbers to help us do this.
The first sentence says, “It is
55 minutes after what.” How do we know from our digital
clock that it’s 55 minutes past something? It’s those digits that come
after the two dots, aren’t they? They show us the number of
minutes that have gone by, 55. So to fill in our first gap, we
need to think how many hours have gone by. It is 55 minutes after 9. At 9:55, it’s 55 minutes after
9 o’clock.
Now, this next sentence is
interesting. It is five minutes before
what. Now, you probably know which
hour of the day we’re going to fill in here. If it’s 55 minutes after 9
o’clock, then the next time will be 10 o’clock, won’t it? So it’s five minutes before
10. But how do we know it’s another
five minutes before 10 o’clock? We know that there are 60
minutes in a whole hour. So if 55 of those minutes have
gone by, there are only another five minutes left before the next hour. And this is why if the time is
55 minutes after 9, it’s also five minutes before 10.
Finally, we’re given four
analog clocks to choose from. And we need to pick the clock
that shows the same time. And there are two ways we could
find this answer, but one’s a lot quicker than the other. Would you rather imagine where
the hands would be at 9 o’clock and count up to 55 or imagine where the hand
should be at 10 o’clock and count backwards five. Counting backwards five is much
quicker, isn’t it?
We know that at an o’clock
time, like 10 o’clock, the minute hand will point directly upwards to the number
12. We also know that the gap
between one number and the next number on the clock face is worth five
minutes. So if the time is only five
minutes before 10 o’clock, we would expect the minute hand to be pointing to the
number 11. It is five minutes away from an
o’clock time. So to begin with, let’s look at
our four clocks. Do any of them show a minute
hand pointing to the number 11?
On the first clock, it’s
pointing to the number 10. So we can forget this
clock. On the second and third clocks,
it’s pointing to the number 11. So these could be the right
answer. And then on the last clock,
it’s pointing to the number 10 again. Don’t get confused by that
short hand that looks like it’s pointing to the number 11. The minute hand is the longer
hand, and here it’s pointing to the 10. So we can forget this clock
too.
To work out which of our two
possible answers is correct, we need to now think about the hour hand. If it’s 9:55, where would you
expect the hour hand to be? Remember, at 9 o’clock, the
hour hand points to the number nine. And at 10 o’clock, it will
point to the number 10. But we haven’t got to 10
o’clock yet. We’re very close though, aren’t
we? We’re only five minutes
away. So we would expect the hour
hand to be almost pointing to the number 10. Can you see which one of our
clocks is correct? It’s this one, isn’t it?
The time on our digital time
said 9:55. And we knew this meant 55
minutes after nine. We could also write the time as
five minutes before 10. And the analog clock that shows
the same time as this is the one where the minute hand is pointing to the number
11. And the hour hand is almost
pointing towards the number 10.
