Sapna who goes to Sacred Heart School, looked at what happens to the letters of the alphabet when they are turned through a half turn, followed by a sideways flip. She drew out the letters one at a time and here are the ones that stay the same:

Of course, it will depend slightly on how you write the letters, but well done Sapna! Sam from Bispham Drive Junior School agreed with this list and explains:

These letters all worked because they have a horizontal line of symmetry. When doing a half turn they are upside down and backwards and flipping them over makes them right.

Can anyone answer the rest of the question? Do these letters stay the same with a half turn followed by a flip from top to bottom?