What is Significand?

The bits of a floating-point number holding its significant digits. For normalized numbers the leading 1 is implied, so single precision stores 23 bits but has 24 bits of precision.

Field: Computer Arithmetic

Significand in the explanations

Questions that mention Significand (19)

  1. How are the bits of an IEEE 754 single-precision (32-bit) number allocated among sign, exponent and significand?
  2. In IEEE 754 double precision (64-bit), how many bits are the exponent and significand?
  3. What is the effect of not storing the leading 1 of the significand (the hidden bit) in IEEE 754 normalized numbers?
  4. Converting −6.25 to single precision, what is the sign–exponent–significand bit string written in hexadecimal?
  5. When training neural networks in FP16 (half precision: 1 sign, 5 exponent, 10 significand bits), which problem tends to arise and is countered by scaling up the loss (loss scaling)?
  6. What is the largest finite value representable in FP16 (1 sign, 5 exponent bits with bias 15, 10 significand bits)?
  7. How are the two FP8 formats, E4M3 (4 exponent, 3 significand bits) and E5M2 (5 exponent, 2 significand bits), usually used?
  8. Which three parts make up an IEEE 754 floating-point number?
  9. In IEEE 754 single precision, if the stored exponent field is 130, what is the actual exponent (power of two)?
  10. What is the hexadecimal bit pattern of decimal 1.0 in IEEE 754 single precision?
  11. Which correctly describes representing decimal 0.1 as a binary floating-point number?
  12. What is the machine epsilon (the gap between 1 and the next larger representable number) in IEEE 754 single precision?
  13. Which gives the approximate number of reliable decimal digits for single and double precision?
  14. Under IEEE 754, what result does the standard specify for dividing a positive number by zero?
  15. In IEEE 754 single precision, what do bit patterns with an all-ones exponent field (255) represent?

Related terms

IEEE 754 NaN Exponent field Backpropagation FP8 Machine epsilon bfloat16 Fixed point GPU Arithmetic shift

Back to the glossary