Replace the question mark with a number
MATH PUZZLE: Can you replace the question mark with a number?Correct answers: 336
The first user who solved this task is Sanja Šabović.
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Sewing machineIn 1857, the first practical U.S. chain-stitch sewing machine was patented by a farmer, James E. A. Gibbs of Mill Point, Va. It was a single-thread, twist-loop, rotary hook design (U.S. No. 17,427). In the same year, he formed the Willcox & Gibbs Sewing Machine Co. with James Willcox, who arranged for its manufacture. Gibbs had invented his own model out of curiosity in 1855, after seeing a newspaper illustration of a sewing machine. When Gibbs saw a tailor's Singer sewing machine, he thought it was too heavy, complicated, and expensive. Willcox and Gibbs sold their chainstitch sewing machine, on a simple iron-frame stand with treadle, for approximately $50, which was half the price of anything similar.« |