Because the reason that any number multiplied by infinity is also infinity is because there was something there to start with. How about 1infinity? What is infinity multiplied by zero? Infinity multiplied by zero results in zero. It may also have to do with conflicting definitions: generally speaking, for some number n, n * 0 = 0, and n * infinity = infinity. I heard something about ohm's law applied to a circuit with an ideal voltage source (which is only theoretically possible) and having the terminals shorted out and at 0 ohms, resulting in the current going up to infinity? 1? Discussions. This is an amusing game but contributes little to mathematics so those in charge simply banned it. Answer with proof required. Division by zero (and the equivalent multiplication by infinity… It's undefined. Does infinity divided by zero theoretically equal any number other than 0 or infinity? Guess not. Infinity minus infinity, due to the nature of infinity, can be zero, infinity, or minus infinity (I - I = -I, 0, I). The answer is 0. Even if infinity is really big, if there are zero amounts of infinity, that would make zero. So what is infinity * 0? Tags: math infinity divide zero 0 ohm s law ideal voltage source. 0*infinity =0 (zero squared really is zero; this simplification is legitimate) OK, that's one of the values you accept so we agree. Why isn't zero multiplied by infinity equal to zero? I read that it this expression is called an "indeterminate form." $0$ multiplied by infinity is the question. This is equivalent to writing zero an infinite number of times and then adding them together. Any number multiply by infinity is infinity or indeterminate. 0 * infinity What is up? Any number multiplied by $0$ is $0$. It is undefined. If there is absolutely nothing you can multiply it by anything you like and still get zero. So long as the number system is a field, anything multiplied by $0$ will necessarily give $0$, even if the "anything" is an infinite number.