The three different notations have an intersection that can be interpreted in each notation with the same result - that is, an uninterrupted sequence of numbers with a maximum of one decimal separator. For a common, interpretable intersaction of the mathematical notation with the scientific notation, a plus/minus sign can be placed directly in front of this digit sequence.
Different handling of blanks in the different notations should be noted. For example, while the character sequence " - 123.456" in the mathematical notation has the value -123 ,456, the above rule in scientific notation would result in value 0. The character "-" followed by a blank is interpreted there as the number and the following characters "123.456" are ignored. For this reason, plus/minus signs should always be aligned directly in front of the digits.