NCERT Mathematics Textbook Solutions for Class 9th
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CHAPTER 1 NUMBER SYSTEMS 1.1 Introduction In your earlier classes, you have learnt about the number line and how to represent various types of numbers on it see Fig. 1.1 .
Fig. 1.1 The number line
Just imagine you start from zero and go on walking along this number line in the positive direction. As far as your eyes can see, there are numbers, numbers and numbers
Now suppose you start walking along the number line, and collecting some of the numbers. Get a bag ready to store them
You might begin with picking up only natural numbers like 1, 2, 3, and so on. You know that this list goes on for ever. Why is this true So, now your bag contains infinitely many natural numbers Recall that we denote this collection by the symbol N.
58 1 N 16 0 5 71 31 652 10 9 4 2 601 7 40 4
Now turn and walk all the way back, pick up zero and put it into the bag. You now have the collection of whole numbers which is denoted by the symbol W.
0 16 3 40 574 2 9 601 2 58