100 Figures Multiplied by 100 Figures!!! Programme of Mr. Z. Dase's Extraordinary Performances with Numbers, on Thursday 18th July, 1850. And Friday and Saturday following. at the Wellington Rooms, 8, Wellington Street, North Strand.

Handbill, 2509 x 130 mm. Johann Martin Zacharias Dase [1824 - 1861] was a German mental calculator who had astonishing calculating skills but little mathematical ability. "He multiplied and divided large numbers in his head, but when the numbers were very large he required considerable time. Schumacher once gave him the numbers 79532853 and 93758479 to be multiplied. From the moment in which they were given to the moment when he had written down the answer, which he had reckoned out in his head, there elapsed 54 seconds. He multiplied mentally two numbers each of 20 figures in 6 minutes; 40 figures in 40 minutes; and 100 figures in 8¾ hours, which last calculation must have made his exhibitions somewhat tiresome to the onlookers. He extracted mentally the square roots of a number of 100 figures in 52 minutes." E W Scripture, Arithmetical Prodigies, The American Journal of Psychology 4 (1) (1891), 1-59.