Replace the question mark with a number
MATH PUZZLE: Can you replace the question mark with a number?Correct answers: 222
The first user who solved this task is Eugenio G. F. de Kereki.
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Richard RobertsBorn 22 Apr 1789; died 16 Mar 1864 at age 74.Welsh mechanical engineer who was versatile in his creativity. One of his earliest inventions was the first successful gas meter. His first patent (1822) was for improvements in looms. He was one of the inventors of the first metal planing machines (1817). Roberts also developed a screw-cutting lathe, and machines for gearcutting and slotting. The self-acting spinning mule (1825) he invented was his most important contribution to the textile industry, which he also set up in France. In the 1830s, his firm built railway locomotives in one of the earliest applications of the use of interchangeable parts. In the 1840s he devised machinery for punching patterns of holes in bridge and boiler plate, automated using punched cards similar to the Jacquard loom. |