Ways to study mathematics while commuting I spend approximately 3 to 4 hours on public transport everyday. I try to maximize the usage of this time by checking email etc on my phone.
Are there any tips to study mathematics while commuting? 
Thanks for sharing! Just want to make full use of the time spent commuting!

The most important tip I have: Think about mathematics. Remember that you are NOT reliant on any phone, computer or even books - all you need are your thoughts. They can serve to be very useful tools, however. Then comes the question what to think about.
I'm sure you run across plenty of interesting problems during your days. What I would do is to get a notebook and write down all such problems, which you then bring along while you commute. Examples could be problems from textbooks, assumptions that are made but never proved (always be sceptical and try to convince yourself of what is true, this is an approach that will be infinitely rewarding in an academic/research career!), famous historical problems, or problems that you come up with yourself. Be creative and have a curious mind!
Then while commuting, go through your list and pick some problem that you find appealing at the moment.
Try to have the habit of always writing down the solutions as well. This will serve to help you remember the problem and the solution better. It is also easy to take short cuts (which could prove to be wrong) if you only solve the problems by thinking. Some of the most successful problem solvers in physics (Feynman and Dirac to name a few) were known to be very strict about writing all solutions down and saving them.
