Real Number System

- All positive and negative numbers including zero are called
**integers**. It is usually denoted by**I**or**Z**.

**I** or **Z** = { ... –3, –2, –1, 0, 1, 2, 3 …}

Here, –1, –2, –3 … are called negative integers whereas 1, 2, 3 … are called positive integers and 0 is taken as neutral.

- The
**absolute value**of an integer is its numerical value regardless of its sign. The absolute value of an integer*n*is denoted as |*n|*.

Therefore, |−10| = 10, |−2| = 2, |0| = 0, |7| = 7 etc.

- The
**opposite of an integer**is the integer with its sign reversed. The opposite of integer*a*is −*a*and the opposite of integer −*b*is +*b*or*b*.

Thus, opposite of 5 is −5, opposite of −8 is 8.

- Integers can be represented on a number line. For this, a line has to be drawn and a point, 0, has to be marked on it. Towards the right of zero, the points, 1, 2, 3 …, are marked at equal gaps. Similar…

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