Negative digits are written by putting the minus sign above the decimal digit, 1, ... , 9. There is no negative 0, because the number 0 is neither negative nor positive.

Are digits always positive?

Using either the Frege or Peano definitions produces a set of natural numbers that are essentially the same as the positive integers. ... Real numbers, however, are always positive, negative, or zero.

Can numbers be negative or positive?

A number is positive if it is greater than zero. A number is negative if it is less than zero. A number is non-negative if it is greater than or equal to zero. A number is non-positive if it is less than or equal to zero.