The two's complement mantissa allows positive and negative values to be stored.

Is logarithm can be negative?

1. You can't take the logarithm of a negative number or of zero. 2. The logarithm of a positive number may be negative or zero.

How do you write a mantissa?

In standard scientific notation, the mantissa is always written with one non-zero digit to the left of the decimal point. So, for example, while 847.13×101 is in scientific notation (with a mantissa of 847.13 ) it is not in standard scientific notation which would be 8.4713×103 .