Video Transcript
This sequence chart will help us
multiply by nine using skip counting by nines up to 10 times. Use skip counting to find nine
times two, and then use skip counting to find nine times nine.
In this question, we’re given a
picture of a sequence chart. If we look at it carefully, we can
see it’s pretty much the same as 100 square. Each row contains 10 numbers, but
instead of having 10 rows that go all the way up to 100, we have nine rows and we
stop at 90. And the reason why we stop at 90 is
that this sequence chart is to help us learn our nine times tables facts. The way it’s been labeled helps us
skip count by nines up to 10 times. The number nine, of course, is one
less than 10.
To count in tens using a chart like
this, we would simply go down a row. Six becomes 16 and then 26. So if that’s how to skip count in
tens using a sequence chart like this, to skip count in nines, we could move down a
square and then back a square. It’s the same as adding 10, taking
away one. And we can see all the multiples of
nine have been labeled on this chart. They make quite a clear diagonal
pattern, don’t they? In the first part of the question
we’re told to use skip counting to find the answer to nine times two, or if we think
of the numbers the other way around two times nine or two lots of nine. Let’s do this then.
Starting at nine, we say nine,
18. Nine times two is 18. Next, we need to use the same skip
counting method. But this time, we need to count a
lot further. We need to count up to nine lots of
nine. So we’ll start at nine again and
say nine, 18, 27, 36, 45, 54, 63, 72, 81. The whole sequence chart only shows
up to 10 times nine, and we’ve said all the numbers apart from one. We’ve skip counted in nines nine
times, and we’ve ended on the number 81. There are lots of patterns with a
nine times table, and we can see some in this sequence chart. We followed the pattern to skip
count by nines to find the answer to two multiplications. Nine times two equals 18, and nine
times nine equals 81.
