Trick: The magician types in 12345678 into a calculator and it is seen displayed on the screen. He explains that 8 is the biggest and also the heaviest number since it uses more pixels. When the magician taps the calculator on the top left corner the number 8 is seen to jump to the opposite end now revealing 81234567.
This looks best with a 10-key calculator with an LCD display. This will work on an iPhone calculator but not an Android calculator because it displays the whole equation. However, Android users can download a calculator app that mimics that of an iPhone so that they can perform this and other effects in this series.