Use the ABS function: `=ABS(A1)`
Multiply by -1: `=A1*-1`
Use Paste Special with Multiply by -1
Use Find and Replace to remove the minus sign
Use a formula with IF: `=IF(A1<0,-A1,A1)`
Use the ABS function: `=ABS(A1)`
Multiply by -1: `=A1*-1`
Use Paste Special with Multiply by -1
Use Find and Replace to remove the minus sign
Use a formula with IF: `=IF(A1<0,-A1,A1)`