Question 1: In general, the number zero did not have its own Roman numeral, but a primitive form (nulla) was known by medieval computists (responsible for calculating the date of ________).
Question 2: This was not a separate letter, but merely a swash variant of i. It is used today, especially in ________, to prevent tampering with or misinterpretation of the numbers after they are written.
Question 4: ________ is often credited for introducing this symbol to represent infinity (∞), and one conjecture is that he based it on this usage, since 1,000 was hyperbolically used to represent very large numbers.
Question 5: In ________, especially the Baltic nations, Roman numerals are used to represent the days of the week in hours-of-operation signs displayed in windows or on doors of businesses.
Question 10: About 725, ________ or one of his colleagues used the letter N, the initial of nulla, in a table of epacts, all written in Roman numerals.