I'm having trouble understanding infinity. My math teacher says it's not a number, and…

Sure! Infinity is a concept rather than a numerical value. It represents the idea of an unbounded quantity, and there exist various forms of infinity such as positive infinity, negative infinity, and cardinality infinity. In mathematics, infinity is utilized to characterize an unbounded magnitude, and the statement "infinity + infinity = infinity" is not always accurate. If one considers the addition of two unbounded magnitudes, it is feasible for the sum to surpass either of the individual quantities. Nevertheless, within certain mathematical contexts, the sum of two infinities is considered to equal infinity.

In conclusion, it is crucial to understand that infinity is not a numerical value in the conventional sense, but rather a concept used to express the notion of "larger than any finite number" or "no limit."