Adding and subtracting using mental methods ... learn simple mental maths and apply it to work out the passcode to open the door. Hypatia, our great mathemagician, sets a question which they ...

Use your mental maths muscle to note down your answer to each of Ralph's questions during the timed pauses. Then be ready to mark your sheet when Matrix gives the answers. At the end total up your ...

These mind-bending challenges offer a unique blend of entertainment and mental ... add 30. Another 1,000. Now add 20. Now add another 1,000. Now add 10. What is the total?” reads the puzzling ...