# Number Systems/ CBSE Class 9 Maths

**CBSE Class 9 Mathematics/Number Systems is about the practice problems for Class 9 Mathematics. Here you can find out Model questions for Class 9 Maths For the Chapter 1.**

**CBSE Class 9 Mathematics Solutions / Number Systems – Chapter 1Extra Questions for Practice/ Model Questions**

Important points to remember:

• The numbers 1, 2, 3———— are called Natural numbers and are denoted by N.

• The numbers 0, 1, 2, 3——– are called Whole numbers and are denoted by the symbol W.

• The numbers ———- -2, -1, 0, 1, 2, ———— are called Integers and is denoted by the symbol Z.

• Numbers that can be written in the form p/q, where p and q are integers and q not equal to zero are called rational numbers. Natural numbers, Integers etc. are rational numbers.

• Numbers that cannot be written in the form p/q are called irrational numbers.