Replace the question mark with a number
MATH PUZZLE: Can you replace the question mark with a number?Correct answers: 131
The first user who solved this task is Rutu Raj.
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Charles FriedelDied 20 Apr 1899 at age 67 (born 12 Mar 1832).French organic chemist and mineralogist who, with the American chemist James Mason Crafts, discovered in 1877 the chemical process known as the Friedel-Crafts reaction. In 1856, after studying in Strasburg, Friedel was appointed conservator of the mineralogical collections at the Superior National School of Mines. In 1871 he began to lecture at the École Normale and in 1876 became professor of mineralogy at the Sorbonne, but on the death of Wurtz in 1884 he exchanged that position for the chair of organic chemistry. He collaborated in efforts to form diamonds artificially, studied the pyroelectric properties of crystals, determined crystallographic constants, and did research on ketone and aldehyde compounds. |