Video Transcript
In which of the following numbers
does the digit nine have the smallest value?
What do you notice about the four
numbers that we’re given in this problem? Well, you might notice that they’re
all made up of three digits. They’re all three-digit
numbers. But if we look more closely, what
else can we see? They’re all made up of the same
three digits, aren’t they? They all contain a one, a nine, and
a two. And you know, we could make some of
these numbers by taking digit cards that have a one, a nine, and a two on them and
just swapping them around. Here’s our second number, our third
number, and our last number.
So we can see that all four
possible answers contain a one, a nine, and a two. But it’s the nine that we really
want to be thinking about because our question asks us, in which of the numbers does
the digit nine have the smallest value? And to be able to answer this
question, we need to think about what the value of each place in a three-digit
number is worth.
Now, we know that the digits in a
three-digit number are worth hundreds, tens, and ones. Here’s a hundred. This is what a ten looks like. And here’s a one. Now, if we look at our four
numbers, we can see that the digit nine sometimes appears in the hundreds place,
sometimes in the middle of the number, which is the tens place, and sometimes in the
ones place. Now, which is the smallest value,
hundreds, tens, or ones?
Well, we know it’s the ones, don’t
we? This is the digit on the right of
the number. And can you see which of our
numbers has a nine in the ones place? The number where the digit nine has
a smallest value is this number here. It’s 129. We know that the smallest value
place in a three-digit number is the ones place. And so we were looking for the
number that had nine in the ones place. Instead of being worth 900 or 90,
the nine in this number is just worth nine. The digit nine has the smallest
value in the number 129.
