Greetings! I am a freelancer at upwork as a front-end developer and I also teach mathematics online. Can I bid for both on upwork?
You should be able to bid for jobs that you have the skills and experience for. If you are confident you can do both, and it will benefit you and your freelancer business that you have both skills on your profile, you may do so. At the end of the day, how you manage your freelancing business will be up to you.
Seeing as you are new here, I would recommend that you read up on these freelancer resources for great tips and insights on how you can work successfully on the platform. For more information about working safely through Upwork, please read these tips for avoiding questionable jobs.