Ever find yourself just needing to know how things work? Before electronic calculators, there were mechanical ones, like the Curta, the only handheld mechanical calculator ever made! I demo’d this at the last Festival of the Spoken Nerd show, and there’s plenty more where that came from. Join us at the Royal Institution, London, on March 2nd for more nerdy demos. Bring your nerdiest friends, they’ll love it. Link to tickets in comments! | Steve Mould

Curta Calculator: before the electronic calculator there was this device that was portable, powered by hand, and could calculate to a precision of 15 decimal places! This is the Type 2 model and it was made in 1962 and still works beautifully. Demonstrated here is how to multiply two large numbers- for fun let’s pick 3803 x 32463. Although the process is not as simple as pressing buttons, the steps are intuitive: First, set in the largest number using the sliders on the side. Next we now multipl

Phoenix Number via Curta Calculator: a crazy property of the “Phoenix number” 142857 is demonstrated on this vintage mechanical calculator. Every turn of the crank handle adds the number in the side register to the top register, hence the top number is the side number multiplied by the number of turns of the crank. Note when 142857 is multiplied by 1 through 6, the same digits appear in the answer and in the same order! 142857 is a cyclic number where integer multiples are numerical anagrams of