How many significant digits does 100.0 have?

Answer 1

1000 has one significant digit (only the 1 is interesting; you don't know anything for sure about the hundreds, tens, or units places; the zeroes may just be placeholders; they may have rounded something off to get this value)

Answer 2:

There is no way to know how many significant digits are in 1000. If you are forced to choose then there is 1 significant digit but, again, there is really no way to tell. If the count of significant digits is important, the number should be expressed in scientific notation.

Answer 2

You count the figures after the decimal point but not before it

* * * * *

The correct answer is 4. All digits, other than zeros used as place holders, are significant digits.

Answer 3

two