Calculate the number 691
NUMBERMANIA: Calculate the number 691 using numbers [6, 2, 6, 4, 42, 561] and basic arithmetic operations (+, -, *, /). Each of the numbers can be used only once.Correct answers: 2
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Five-needle telegraph demonstratedIn 1837, the five-needle telegraph was demonstrated by English inventors, Charles Wheatstone and William Fothergill Cooke. They ran a six-wire telegraph line 2.4-km from Euston to Camden Town along the Great Western Railway Company railway track. They successfully transmitted and received messages. Wheatstone provided the technological skill and is better remembered in the history of the telegraph while Cooke had the business acumen. This first patent (1837) was impractical because the code used simultaneous combinations of five keys, and so was rather cumbersome, limited to only twenty letters (J, C, Q, U, X and Z were omitted). By 1845, they patented the more important single-needle electric telegraph.« |