Albert Einstein once wrote on a chalkboard:9 x 1 = 99 x 2 = 189 x 3 = 279 x 4 = 369 x 5 = 459 x 6 = 549 x 7 = 639 x 8 = 729 x 9 = 819 x 10 = 91

Suddenly chaos erupted in the classroom because Einstein made a mistake. Obviously, the correct answer to 9 × 10 isn’t 91. And all his […]