Updated: Aug 19, 2020
Many times when students are asked as to what the Additive Identity of a number is, I either get a blank stare or the infamous "HUH?" Other times, I hear the most interesting theories which lead to big discussions and debates, causing me to wonder endlessly alongside them . . .
Anyway, so I break it down and ask students "What can I add to a number without changing its value?. In other words, what can I add to 29 so that the number remains 29"?
My students roll their eyes and say " That's easy! ZERO.... Is that all you were asking about?"
That's it! These are the fundamental basic principles we really want to consolidate before moving forward.
The Indian mathematician and astronomer Brahmagupta Siddhanta was the first to consider the implications of zero as a number in its own right.In his book "The Opening of the Universe," Brahmagupta was the first to lay out rules of zero.
Here's the kicker: Brahmagupta lived around 600 A.D. Let's just consider that for a moment. Mathematicians have been pondering the significance of zero for over 1400 years! For a concept that appears so simple, it becomes evident that quite a lot of thought has gone into it.
Key Takeaway: If you add or subtract zero from a number, that number doesn't change. It maintains its identity, so modern Mathematicians refer to zero as the Additive Identity.
1+ 0 = 1
1- 0 = 1