Not sure how to answer or do this question..

Q1. What regular expression would you use to find a credit card number? Write the regular expression below and at least two examples of a credit card number that your regular expression can match.

So for an example I have made a fake number , how do I write the regular expression?

4440 9987 9923 7783

4440-9987-9923-7783

Q2.What regular expression would you use to find a URL? Write the regular expression below and at least two examples of an URL that your regular expression can match.

www.google.com

http://www.nytimes.com

What would be the expression? Please help. Thanks