Video Transcript
Which set of numbers is ordered
from greatest to least? Five, six, seven, eight, nine. Five, seven, six, eight, nine. Or nine, eight, seven, six,
five.
We’re given three sets of numbers
here. And we’re asked which one of them
is ordered from greatest to least. These last three words in the
question are really important because as we read through our sets of numbers, we
might have heard one set of numbers that sounded like it might be right. But before we start looking, we
need to think about these last three words. What does it mean to order a set of
numbers from greatest to least? We know that another way of saying
the word greatest is largest, and another way of saying least is smallest.
We’re looking for a set of numbers
that starts with the largest number and goes down and down and down until we get to
the smallest number. You know when you walk down some
stairs, we might say, “I’m descending the stairs.” Or going from greatest to least is
descending order. We want our set of numbers to go
down. Let’s use a number track to help us
here. Now, we know that the numbers on
the number track are written in order. If we read them from left to right,
we start with the number one and we end with the number 10. They go up; they go from the least
to the greatest.
But our question asked us to look
for a set of numbers that’s in order from greatest to least. So, we need to read our number
track in the opposite direction, from right to left, starting with the number 10 and
ending with the number one. Now, which of our set of numbers is
in this order? Let’s jump along our number track
and see what we find. Our first set of numbers, five,
six, seven, eight, nine. Well, these numbers are in
order. We set them one after each
other. But we’re travelling in the wrong
direction here. We’re going from least to
greatest. Our numbers are getting bigger each
time. Five, six, seven, eight, nine. This is not descending order. This is ascending order. Our numbers are getting larger. But this set is not the correct
answer.
Let’s try our second set. We’re starting with the number five
again, seven, six. Well, let’s just stop there. These numbers are not in any kind
of order. We’re traveling in all sorts of
directions. The numbers five, seven, six,
eight, nine are not in order at all. What about our final set of numbers
starting with the number nine? Eight, seven. This looks like it could be the
correct answer; we’re traveling in the right direction. Our numbers are getting
smaller. Six, five. We can see that we started with the
greatest of our numbers, which was nine. And we’ve ended with the least,
which was the number five. Our numbers got smaller and smaller
each time. Nine, eight, seven, six, five. It’s the same as counting
backwards, isn’t it?
It would have been very easy to
think that the right answer was five, six, seven, eight, nine because we used to say
numbers that way. But we read the question really
carefully. And we saw that we we’re being
asked for a set of numbers that was ordered from greatest to least. And that set of numbers is nine,
eight, seven, six, five.
