Arranging numbers in ascending or descending order are called ordering of numbers .

Ascending order - Arranging numbers from smaller to larger value is called ascending order.
e.g. 5 < 12< 25< 30< 45< 50 .

Descending order- Arranging numbers from larger to smaller value is called descending order.
e.g . 50> 45 > 30 > 25 > 19 > 11 > 5 .