 It's important to understand that division has a problem when it comes to the number zero. Suppose A is a number not equal to zero. Then for A divided by zero we're asking what number when multiplied by zero will give us A. But no matter what number we multiply by zero you will always get zero, never A. So A over zero has no meaning. We say it is undefined. Now if A is zero we're asking what number when multiplied by zero would give us zero. The answer is any number at all because any number multiplied by zero would give us zero. This makes zero divided by zero completely undetermined. It can be any number you can think of. This is what gave us the one equals two result. The problem with zero also shows up with exponents. For any number A and any positive integer n we define A the base raised to the nth power the exponent to be the base multiplied by itself the number of times specified by the exponent. We see that when we multiply two numbers with the same base we can add the exponents. With that in mind we define a negative exponent to mean one divided by the base raised to the positive value of the exponent. This extends the exponent arithmetic to include all integers. It follows that A raised to the nth power times A raised to the minus nth power will equal the number one. It also follows that A raised to the nth power times A raised to the minus nth power will equal A raised to the power of zero. So in order for the arithmetic to hold we must define a number multiplied by itself zero times to equal the number one the multiplicative identity. This is much like adding a number to itself zero times is equal to zero the additive identity. But we also know that if the base is zero raising it to any power will always give you zero. So what if both the base and the exponent are zero? Does zero raise to the zero power equal one or does zero raise to the zero power equal zero? It is said to be indeterminate. So when we apply math to a physical situation we must always take care to never wind up dividing by zero. We must always stipulate the ranges where an equation is operative and where it is not.