# The Additive Identity: What's 1+0?

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**