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Waheed Fawzy

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297. Timothy Cooper 6
298. Waheed Fawzy 6
299. Joni Allen 6
300. יוסף שעשוע 6
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MATH PUZZLE: Can you replace the question mark with a number?
MATH PUZZLE: Can you replace the question mark with a number?
MATH PUZZLE: Can you replace the question mark with a number?

First dated printed arithmetic book

In 1478, the anonymous Arte dell'Abbaco(“The Art of the Abacus”), printed in Treviso, Italy had this publication date. It is the first dated printed book on arithmetic. The unknown author was likely a priest, and it was dedicated to some of his young friends who kept asking for it. The printer was probably Geradus de Lisa, dé Flandria. The 124-page text dealt with commercial applications of arithmetic, so the language was the local vernacular Venetian dialect, not the scholarly Latin used for the abstract studies of universities. The book teaches the four main operations, with numerous examples, and the concept of fractions (but not the as yet unknown decimals). He shows how to calculate the date of the new Moon. Although some pamphlets on Algorithmus are possibly older than this book, they are undated.«[Image: detail of a calculation shown in the book.]

Ballpen in space

When NASA first started sending up astronauts, they quickly discovered that ballpoint pens would not work in zero gravity.
To combat the problem, NASA scientists spent a decade and $12 billion to develop a pen that writes in zero gravity, upside down, underwater, on almost any surface including glass and at temperatures ranging from below freezing to 300 C.
The Russians used a pencil.

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