Video Transcript
Subtract 10 each time when skip
counting backward by 10s. Fill in the next three
numbers.
Can you see what we have in the
picture here? It’s a number line, but it’s a
number line with a difference. You might be used to number
lines that go from left to right, and we read along them. Well, in the picture, we can
see a number line that goes up and down, and we’re going to need to read it
looking up and down. We can see that there are some
numbers at the top of this number line. So let’s start at the top and
read down. 120, 110, 100. And then we have three empty
boxes. And we can see at the bottom of
the question that we’re going to need to fill in these next three numbers.
To do that, we need to
understand what’s happening on our number line. In the first sentence, we’re
told how to find the answer. We need to skip count backward
by 10s. If we look at the other side of
our number line, we can see some green arrows that say subtract 10, subtract
10. So what’s happening as we’re
going from 120 to 110 to 100 is we’re taking away 10 or counting backward in 10
every time. So, to fill in the next three
numbers, we need to carry on skip counting backward by 10s. But we’re going to start with a
number that we got to, which was 100.
Now, 100 is the same as 10 lots
of 10. As we skip count backwards in
10s, we need to take away one more lot of 10 every time. So instead of 10 10s, we’re
going to have nine 10s. And nine 10s are worth 90. If we subtract another lot of
10, we’re going to go from nine 10s to eight 10s, and 90 becomes 80. And if we subtract one more 10
from 80, we’re going to have 70. We carried on skip counting
backward by 10s by subtracting 10 every time: 120, 110, 100, 90, 80, 70. The missing three numbers in
our pattern were 90, 80, and then 70.
