Negative of a number means, if the number is positive then we have to add a "-" symbol to it and if the number is negative then we have to remove the "-" symbol from it.
Negative of −27 is 27.
Negative of 0.89 is -0.89 = −89100.
Negative of -66 is 66 = 1983.
Negative of 31 is -31.