You probably learned that you can't take the square root of a negative number. Your calculator throws an error. Your teacher said it's impossible. Then suddenly, in algebra or precalculus, someone int...

You're standing in line at the coffee shop, splitting a bill with friends, or helping your child with homework. The numbers are simple enough, but reaching for your phone feels awkward. What if you co...

Division by zero seems like it should work. After all, you can divide by one, by ten, by a million. But try dividing by zero on your calculator and you'll get an error message. Some calculators say "u...