I get a fun email from Mental Floss about 4 days a week- some little trivial something that someone found and wrote up. Today's was interesting to me because... When first arriving to Ukraine in 2000, it was immensely interesting to watch cashiers ring up your purchase on a cash register and then double-check it on their abacus! I haven't seen that in a LONG time but this brought back some chuckles from back then! I simply copied and pasted the entire email: 

March 29, 2012
The Strangest Way to Double-check your Calculator

Neatorama pointed us to this incredible story about hybrid calculators from the late 70's. Apparently, when digital calculators were still gaining acceptance, Japanese abacus users were skeptical of relying on the technology. To ease the transition, between 1978 and 1985, Sharp made three different models of hybrid calculators so that people could double-check the electronic math with the more familiar system! Pretty incredible. Retrocalculators.com has a deeper explanation of the product launches with more photos if you're interested, and some wonderful links as well. Oh, and if you want to see some bizarre blueprints of rotary phones, our pal David Israel has a crazy page on those here.