It is 9th century AD. For several centuries mathematicians in Egypt and Mesopotamia had designed elaborate numeral systems without the number zero, many using placeholder variables and even punctuation marks to work around instead. That is until Indian mathematician Bhramagupta formally introduced zero as part of the numerical system. He is attempting to tell a grain merchant, Siddantha, about his discovery.
Bhramagupta: Do you get it now?
Siddantha: I still have no idea what you’re talking about.
Bhramagupta: Ok, if I have a single pebble, how many pebbles do I have?
Siddantha: You have one.
Bhramagupta: Right. Now what if I don’t have any pebbles? How many pebbles is that?
Siddantha: Yeah, this is where you’re losing me.
Bhramagupta: What number is none?
Siddantha: How can you have a number for nothing? It’s nothing.
Bhramagupta: Right, but that’s my point. Let’s say I have twelve carts of hay and then you take those twelve carts of hay. How many carts of hay do I have left?
Siddantha: You don’t have any?
Bhramagupta: Right. So if I wanted to write down that I had nothing, how would I do that?
Siddantha: What’s the point of writing down that you have nothing? Seems like a waste of papyrus.
Bhramagupta: Yes but we need a way to formally express that value.
Siddantha: What value?
Bhramagupta: The value of nothing.
Bhramagupta: I call it zero. Here, I’ll draw the symbol for you.
Siddantha: That look like the letter “O.” Now you’re just being confusing on purpose.
Bhramagupta: No, it’s zero.
Siddantha: Ok, I’ll play along. Zero, as you call it, is a number just like five or seven even though it’s value is nothing.
Siddantha: Can I divide a number like seven by this zero?
Siddantha: What? Why?
Bhramagupta: That’s just…like impossible.