The expression $\frac{1}{0}$ is undefined in mathematics. Here's why:

• Division by zero is not allowed because there is no number that, when multiplied by 0, gives 1. In other words, dividing by zero doesn't make sense in the real number system.

If you have any questions or want more details, feel free to ask!

Here are 5 related questions:

1. Why is division by zero undefined in calculus?
2. What happens when you divide by a very small number close to zero?
3. How does division by zero relate to limits in calculus?
4. What is the difference between an undefined expression and an indeterminate form?
5. How do calculators handle division by zero?

Tip: When solving equations, always check for division by zero to avoid undefined results.