RegEx: How can I match all numbers greater than 49?

Question

I\'m somewhat new to regular expressions and am writing validation for a quantity field where regular expressions need to be used.

How can I match a

Answer 1

Next matches all greater or equal to 11100:

^([1-9][1-9][1-9]\d{2}\d*|[1-9][2-9]\d{3}\d*|[2-9]\d{4}\d*|\d{6}\d*)$

For greater or equal 50:

^([5-9]\d{1}\d*|\d{3}\d*)$

See pattern and modify to any number. Also it would be great to find some recursive forward/backward operators for large numbers.