The fractional or decimal part of a logarithm of a number. For example, the logarithm of 163 is 2.212. The mantissa is 0.212, and the characteristic is 2.0. In floating-point numbers, the mantissa is the number part. For example, the number 24 can be written as 24, 2 where 24 is the mantissa and 2 is the exponent. The floating-point number is read as .24 × 102, or 24.