# What exactly is significand?

per wiki, The significand is part of a number in scientific notation or a floating-point number, consisting of its significant digits.

in this example $$123.45 = 0.12345 × 10^3$$

which part is The significand? is it 0.12345? or just 12345

• I think the significand is everything other than the ${}\times 10^k$. May 16, 2019 at 21:06

In general, the significand is the part that varies depending on the measurement precision. In standard form (a number written like $$a \times 10^{n}$$), the significand is $$a$$, which is the original number stripped of all leading and trailing zeros. Clearly, the number of digits of $$a$$ tells us how precise the number is, and $$n$$ just tells us the order of magnitude of the number.
There is no real consensus on whether the significand should be an integer, or be between $$0$$ and $$1$$, or anything else. In your case it could be either depending on how you choose to express it. If you are writing the number as $$0.12345 \times 10^3$$, then the significand certainly is $$0.12345$$.