First, there's always graduate school. Math is a fantastic subject to learn more about, just because (like many other things). After she could probably get into academia or industry (industry at a higher level).
Second, the people I know from undergrad with math degrees, who did not go to graduate school, chose one of three options:
1.) Work for a financial company doing number crunching of some sort
2.) Taking the actuarial exams
3.) Computer companies: but I've heard from them that at job fairs, computer companies that want to hire math majors always want to know the amount of programming experience you have
My two cents
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