The Right Answer? 8,186,699,633,530,061 (An Abacus Makes It Look Almost Easy)

The abacus is still taught in Japanese schools, although not as intensively as it once was. But the centuries-old tool is still popular, and national tournaments attract elite competitors.

from Pocket https://www.nytimes.com/2019/08/21/world/asia/japan-abacus.html
via TV Aerials Leeds