9
votes
1answer
147 views

Today is the square-root of 25th day of the omer

If you haven't counted sefirat haomer yet that night, you're not supposed to say the current day (for example, 'today is the 5th day') before making the bracha. But what about saying what today is in ...
4
votes
0answers
82 views

Slide Rule on Shabbos/Yom Tov

May a slide rule (mechanical device before calculators) can be used on Shabbos for Gemara calculations?
8
votes
2answers
476 views

Magen Avraham - Practically no Plag HaMinḼah or just no Plag HaMinḼah in winter?

Calling all science and math-oriented Judaism.SE-ers! According to the website MyZmanim.com, today's Halachic times where I work are as follows (only a handful of times are shown because the question ...