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Monthly Archive - December 2021 (page 4)brain teasers, puzzles, riddles, mathematical problems, mastermind, cinemania... These are the tasks listed 31 to 40. |
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If c3b95 - bb70b = 7ba9a find number abc. Multiple solutions may exist. | 1. |  |
H Tav | 5861 |
| 2. |  |
c. raj. | 5777 |
| 3. |  |
Nasrin 24 T | 5731 |
| 4. |  |
Fazil Hashim | 5718 |
| 5. |  |
Thinh Ddh | 5557 |
| 6. |  |
Alfa Omega | 4681 |
| 7. |  |
Djordje Timotijevic | 4549 |
| 8. |  |
Mita Kojd | 4525 |
| 9. | Jakubovski Vladimir | 4443 |
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| 10. | Chandu Rajyaguru | 4419 |
Jacob PerkinsBorn 9 Jul 1766; died 30 Jul 1849 at age 83.Jacob Perkins was an American inventor, of Newburyport, Mass., a Freemason, who produced innovations in diverse fields. For example, in 1794, under his patent of January 16 of that year, he made the first nails which were both cut and headed by machine in America. Around 1817, he installed a hot air furnace of his own design in the Massachusetts Medical College. While living in London, England, he advocated high pressure steam techniques and designed in 1827-28 a steam gun for the French Government. Also, Perkins advanced the art of engraving and platemaking for bank notes. In 1834, he was issued the first US patent for a refrigerating machine for sulphuric ether compression in a closed cycle. (It utilized a concept displayed by Oliver Evans, 1805.) Back in England, he printed 64 million of the first penny postage stamp in 1840. |