How to get a specific length of digits (5 or 10) with a regular expression?

Question

Regular Expressions

How can I write a regular expression that checks the following condition: " only digits of 5 or 10 characters are allowed "?

The option [0-9]{5}|[0-9]{10}does not fit, and I can not think of an alternative.

Answer 1

^(\d{5}){1,2}$