The following steps show how to bulk convert negative or positive numbers.
 Negative numbers (1) become positive numbers (1)
 Positive numbers (1) become negative numbers (1)
There are two ways you can do this.
Method 1: Using a formula
This method leaves the original numbers are they are and creates another set of numbers.
 In a empty cell in the same row – use a formula like below – note how it takes the original value and multiples it by negative 1 (1)

=SUM(A2*1)
 Copy the formula down the column to repeat for the other numbers
 The formula returns the inverse number
Method 2: Using special paste
This method will convert the numbers using the “multiply” special paste.
 In an empty cell type 1
 With the cell selected, copy it
 Select the numbers you want to convert
 Rightclick on the selection
 Click on ‘Paste Special’
 Under ‘Paste’ choose ‘Values’
 and under ‘Operation‘ choose ‘Multiply’
 Click ‘OK’