What number comes next?
Look at the series (2, 3, 6, 21, 231), determine the pattern, and find the value of the next number!Correct answers: 56
The first user who solved this task is Slobodan Strelac.
#brainteasers #math
Micrometer screw guage patentIn 1890, Laroy Sunderland Starrett received a U.S. patent for his micrometer screw guage (No. 433,311), which is the form still familiar and indispensible to any machinist or person measuring small objects in a physics lab. Since 1881, he had worked to improve the micrometers then existing. His design had a vernier scale, a smaller head, a locking device and a small knob extending from the barrel to enable quick rotation while closing the initial gap to the inserted object being measured. By 1899, his micrometer was available in a one-inch size for $6.50, including a leather case. He took out many other patents for the tools he invented or improved, and established a substantial tool manufacturing business.« |