BRAIN TEASERS

# Calculate the number 9425

NUMBERMANIA: Calculate the number 9425 using numbers [7, 8, 9, 1, 46, 583] and basic arithmetic operations (+, -, *, /). Each of the numbers can be used only once.
The first user who solved this task is Roxana zavari.
#brainteasers #math #numbermania

Two blondes were recently observed in a parking lot trying to unlock the door of their Mercedes with a coat hanger. Here is their dialogue:
Blonde One: I can't seem to get this door unlocked!
Blonde Two: Well, you'd better hurry up and try harder! it's starting to rain, and the top is down!
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### Simon Lake submarine patent

In 1897, a U.S. patent was issused for a "Submarine Vessel" invented by Simon Lake (No. 581,213). It described oscillatory lateral vanes on the sides of the vessel to set for ascending or descending, a weight to shift fore-and-aft to keep the vessel on an even keel, a compressed air reservoir, ballast tanks, an "air-tight diver's chamber provided at the bottom with a trap" (suitable for diving salvage operations), and wheels to travel on the water-bed which could be propelled and steered from within. Lake was interested in the use of a submarine for commercial, rather than military, purposes. It had a hinged observation tube, which could be provided with a mirror (forerunner of the perioscope). It was expected to be steam-powered on the surface (but in practice the heat generated by the boiler was intolerable to a crew, and thus impracticable.)«[Image: rear view of submarine, showing hull with lateral vanes, wheels and propeller.]
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