Two detectives - Tom and Mark, are solving a murder mystery. They suspect that the murderer (or rather, the one who ordered the murder) is a very popular politician, Sean. So, they are secretly investigating the case.
One day, Mark receives this SMS on his phone, from Tom:
Sean knows us. I'm Hiding. Open your door.
Mark opens his door, and finds a bag, full of dairy items and groceries. He searches the bag, and finds a notebook. The notebook is all new, and only one page has been written upon.
The page looks like the maths homework of a 7-year old student. It contains the following text:
After going through this page, Mark understands where Tom is hiding.
So, where is Tom hiding, and how did Mark know this?
P.S. This is my first puzzle on this site, and I am not very familiar with tags. So please correct the tags if you think I missed something