How to express negative numbers in scientific notation?

I used -25 as an example:

= -2.5 × 101
(scientific notation)

= -2.5e1
(scientific e notation)

= -25 × 100
(engineering notation)
(one)

= -25
(real number)

Scientific notation is used to express very large or very small numbers. A number in scientific notation is written as the product of a number (integer or decimal) and a power of 10. The number has one digit to the left of the decimal point. The power of ten indicates how many places the decimal point was moved.

Do the inverse operation