Negative number

A negative number is indicated by a _ (underbar), not a - (minus).

5 + _3
2

   _7
_7 

   _5e_3
_0.005

   5 - 9
_4

Leaving out the blank between the - and the 9 does not change the meaning.

 5 -9
_4

The - is always a verb. This simplifies the rules for evaluating sentences as there is no special case for - when it is used immediately to the left of a number. But if - is always a verb, then another character, the _ (underbar) is required to spell a negative number.

The _ is used in spelling numbers, along with the digits, dot, and the e for exponential notation; it indicates a negative number.

Remember: _ in front of a number is part of the number and indicates that it is negative, and - is always a verb and is not part of a number.

The __ (two underbars) is negative infinity and is a number.