How to add Negative sign to all value？

[phoebe_90]

change sheet1 to sheet2

Account	Amount
24508210	6.68
68121000	-6.68
24508210	33.85
24508210	4.28
24508210	24.00
24508210	31.56
24508210	64.46
24508210	48.13
64015000	-48.13
65031000	-33.85
65080000	-24.00
66010000	-677.32
66020000	-4.28
66020000	-31.56
66020000	-64.46

sheet2

Account	Amount
24508210	-6.68
68121000	6.68
24508210	-33.85
24508210	-4.28
24508210	-24.00
24508210	-31.56
24508210	-64.46
24508210	-48.13
24508210	-677.32
64015000	48.13
65031000	33.85
65080000	24.00
66010000	677.32
66020000	4.28
66020000	31.56
66020000	64.46

[BS_THE_ANALYST]

@phoebe_90 you just need to use a formula tool like so:

Mutiply the column by -1

[BS_THE_ANALYST · Accepted solution]

@phoebe_90 if you want to overwrite the existing column, instead of creating a new one:

[JitendraPal]

First of all, change the data type for the Amount field to either Double or Float by using select tool, then use the formula tool ([Amount]* (-1)) to get the desired result. 

[Arjunmarwaha09]

looks good