Answer:
M + 20 cookies.
Explanation:
The number of cookies that Chandler has can be represented by the expression M + 20, where M is the number of cookies that Monica has. This is because it is given that Chandler has 20 more cookies than Monica, so we need to add 20 to Monica's number of cookies to get Chandler's number of cookies. Therefore, if Monica has M cookies, then Chandler has M + 20 cookies.