Video Transcript
This robot multiplies any input by
eight to give an output. If we give the robot an input of
two, it will give an output of 16, which is eight times two. What would the output of the robot
in the following case be? That’s where there’s an input of
four. And then what would the output of
the robot in the following case be? This is when there’s an input of
nine.
So, so far in this question, we’ve
seen that we’ve got a times table robot, which must be a very useful robot to
have. What goes in gets multiplied by
eight and then we get the answer. In the first picture, we can see
that the input is four. This is then going to be multiplied
by eight. We can think of this as four lots
of eight. Let’s count in eights four times to
find the answer. Eight, 16, 24, 32. Four lots of eight are 32. And so, we know that the number the
robot’s going to come out with, its output is going to be 32.
In the second part of the question,
we’re given a new input. What happens if we put the number
nine into our robot? Well, we know it’s going to be
multiplied by eight again. So, what are nine eights? We could use skip counting to help,
just like we did with the first part. But this time, let’s use a doubling
fact. If we know what four nines are,
maybe we could use this to help us find eight nines. Four nines or nine times four
equals 36. And because eight is four doubled,
the answer to nine times eight is going to be nine times four doubled. And 36 doubled is 72. Four times eight equals 32. So, if the input is four, the
output will be 32. And nine times eight equals 72. So, if the input is nine, the
output will be 72.
