What is the missing number?
What is the missing number?Correct answers: 66
The first user who solved this task is Nasrin 24 T.
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Sir Joseph WhitworthBorn 21 Dec 1803; died 22 Jan 1887 at age 83.English mechanical engineer (Baronet), who pioneered precision measurement. He held many patents for machine tools, textile and knitting machinery, and road-sweeping machines. He originated a scraping technique to make a true plane surface (1825). He advocated using the decimal system. In 1841, his standard screw threads were adopted by the Woolwich Arsenal. By 1851 Whitworth's machine tools were internationally known for their accuracy and quality, as well as his screw cutting lathes, his planing, drilling, slotting, and shaping machines, and his millionth-part measuring machine. He also did pioneering work in ordnance, creating a method for casting ductile steel to replace hard steel, which is subject to fracture.« |