**What is the pattern of numbers?**

**PATTERNS**

Patterns arise due to special arrangements of numbers associated with geometrical figures. The numbers are of different kinds like

- Natural numbers
- Polygonal numbers

(a) Triangular numbers

(b) Square numbers

(c) Pentagonal numbers

(d) Hexagonal numbers, etc.

**Examples**

**1. Patterns in natural numbers**

**2. Patterns in polygonal numbers**

**(a) Triangular numbers:**

Here the numbers of dots up to any stage are given by the pattern

1, 3, 6, 10, 15, ……

These numbers arise from triangles and so these are called triangular numbers.

**(b) Square numbers:**

Here the numbers of dots upto any stage are given by the pattern

1, 4, 9, 16, 25, 36, ……

These numbers arise from squares and are called square numbers.