how to match a number which is less than or equal to 100?

Question

I want to match a number which is less than or equal to 100, it can be anything within 0-100, but the regex should not match for a number which is greater than 100 like 120,

Answer 1

this matches 0 to 100

^0*([0-9]|[1-8][0-9]|9[0-9]|100)$