MATH PUZZLE Time

When multiplied by itself, which number is equal to

12,345,678,987,654,321?

Speaking in terms of total geographic area, which of these statements is true?

In chemistry class, you can enjoy all the primary colors just by observing sulfur, since it burns blue, is yellow when solid, and melts into what color liquid?

Which number in Roman numeral value equals 1600?

Which of the following countries do NOT border each other at all?

What is the value of x when 12 over x equals 9 over 6?

What country that borderd both Red Sea and the Meditteranean Sea is the most populous country in the Arab world?