This calculator has been specially modified so that when the equals button is pressed it brings up your force number. There are endless possibilites with this, from predictions, to book tests, to making random calculations result in 80085. This is supplied with basic instructions on how to use the force function, however the way you use the force is left for you to decide.
Because this works by using the memory function on the calculator, a letter “m” is visible on the left hand side of the screen when the force is set. I personally use this to verify that the force is set, however Richard Osterlind suggests a piece of tape covering that edge of the screen. I have therefore made 2 versions available, one with tape and one without. In addition to covering the “m” the tape also covers the minus symbol so calculations involving negative numbers will not display correctly on the tape version.
Uses of this kind of an idea started in 1975. Early practitioners were John Sherwood, Bayard Grimshaw and Vic Perry. (Thank you to Mark Strivings for help with crediting)
Due to international shipping rules the battery is not included for sales outside of the UK, however it takes a single AA battery which should be easy enough to acquire in most countries.