Video Transcript
Is 21,442 less than, equal to, or
greater than 21,942?
In this question, we’ve got two
five-digit numbers to compare. But did you notice something about
these numbers as we read them? They both begin with the same
number of thousand, 21,000. It’s only the last part of each
number that’s different. This means the numbers must be
quite close together. We could use a number line to help
compare them.
If both numbers are twenty-one
thousand and something, they must come somewhere between 21,000 and 22,000 on a
number line. When we’re using a number line like
this is always helpful to mark the midway point. And that’s 21,500. So, where does our first number
belong on this number line? Where would you put 21,442? Well, twenty-one thousand four
hundred and something is just less than 21,500, our midway point. We could estimate that this number
is about here.
Now, where does our second number
belong? Again, the digit we need to be
looking at is the hundreds digit. We know that the ten thousands and
the thousands digits are the same. This number is twenty-one thousand
nine hundred and something. This is very close to 22,000, isn’t
it? And now, we can use our number line
to answer the question. We can see that 21,442 is less than
21,942. The correct answer to this question
is to use the symbol that represents less than.
