NCERT Book Class 6 Mathematics Chapter 10 The Other Side of Zero

10 THE OTHER SIDE OF
ZERO
Integers
More and ore numbers!
Recall that the very first numbers we learned about in the study of
mathematics were the counting numbers 1, 2, 3, 4, …
Then we learned that there are even more numbers! For example,
there is the number 0 (zero), representing nothing, which comes before
1. The number 0 has a very important history in India and now in the
world. For example, around the world we learn to write numbers in
the Indian number system using the digits 0 to 9, allowing us to write
numbers however large or however small using just these 10 digits.
We then learned about more numbers that exist between the
numbers 0, 1, 2, 3, 4, … , such as 1 , 3 , and 13 . These are called
2 2 6
fractions.
But are there still more numbers? Well, 0 is an additional number
that we didn’t know about earlier, and it comes before 1 and is less
than 1. Are there perhaps more numbers that come before 0 and are
less than 0?
Phrased another way, we have seen the number line:

0 1 2 3 4 5 6 7 8 9 10

However, this is actually only a number ‘ray’, in the language we
learned earlier in geometry; this ray starts at 0 and goes forever to
the right. Do there exist numbers to the left of 0, so that this number
ray can be completed to a true number line?
That is what we will investigate in this chapter!
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