Thousands of years ago, numbers were originally developed for accounting purposes, in order to keep official records of transactions between people. So, there were only ever just whole numbers of things, such as sheep and spears. Of course, as more people began to own more things, numbers grew right along with everything else in the economy. As such, societies like that of the Ancient Egyptians and Ancient Greeks began to use blank spaces as placeholders in large numbers. Since there were still only nine different digits, the number five hundred four had to be written as 5_4, not 504. That is to say that, there wasn’t actually any digit in the tens place. This may not seem like that big of a difference, but it is. Prior to the use of zero there was no decimal system, at least not one based on the numbers 0, 1, 2, 3, 4, 5, 6, 7, 8 and 9.

It wasn’t until the Ancient Indians finally devised the concept of the number zero, represented by the symbol 0, that the contemporary Base-10 number system finally emerged out of the classical one. This was very important, because zero is both a number and the numerical digit used to represent that number in numerals, which makes it more than just a simple placeholder value. Granted, the digit 0 is used as a placeholder in place value systems, but the number 0 also fulfills a central role in mathematics as the additive identity of integers, among many other things. In line with this, zero is a rather unusual kind of number. For one thing, it isn’t positive or negative. It is, however, even rather than odd. Zero is definitely an even number, for a whole lot of different reasons. For one thing, 0 falls between two odd numbers on the number line, namely -1 and 1. Plus, zero is a multiple of two, because 2 times 0 is still 0. Zero is also divisible by two (0/2=0). It follows every rule in the book, such that zero plus an even number will even produce an even sum (4+0=4).

Of course, there are a lot of strange rules for zero as well. As an example of what I mean, it’s impossible to have zero to the power of zero (0⁰). Along with this, it’s also impossible to divide any number by zero (10/0). As a general rule, dividing by smaller and smaller numbers will always give you bigger and bigger results. For instance, 10 divided by 10 equals 1, 10 divided by 5 is 2, 10 divided by 1 is 10, 10 divided by 1/2 is 20, and so on and so forth. Therefore, following that pattern, it should theoretically be possible to divide all the way down to zero, yielding the largest possible solution. This would just make ten divided by zero equal to infinity, but that’s not what happens, not really. Instead, all that is really known for sure is that dividing by a number that tends toward zero leads to an answer that tends toward infinity. The thing to understand is that infinity doesn’t mean everything, and zero doesn’t mean nothing, which isn’t even something at all. This is why the solution to any division problem with zero as the divisor is technically undefined.

For this and many other reasons, in spite of it being the greatest discovery in the history of mathematics, European scholars were actually quite reluctant to adopt the use of the number zero. All the way up into the Middle Ages, people in Europe continued to use outdated Roman numerals (I, II, III, IV, V, VI, VII, VIII, IX, X,…), in part because the Arabic numerals were very easy to alter. Since everything was handwritten back then, merchants were upset by the curly nature of the numbers six (6), nine (9), and zero (0), which could be misleading in the marketplace. In addition to that, the concept of zero also opened the door to negative numbers, which the naive Europeans didn’t like either. Having predominantly converted to Christianity by then, they believed the number zero to be the work of the Devil. Fortunately, they finally started getting over their superstitious beliefs in the 13th century. Now, thanks to the great Italian mathematician Fibonacci, everyone in the modern world makes use of the same universal language, based on ten digits, beginning with the all-important number zero.