Question

How many significant figures are in the number 5400?

Answer 1

I am assuming that `5400` is `5400` as-written.

As such, `5400` is relevant to the following rules for significant figures:

PROMINENT DEFINITIONS

• All nonzero digits are significant.
• A trailing zero goes after a decimal point, or after all nonzero digits, or both, and no nonzero digits follow it.

SPECIAL CONDITIONS

• All "placeholder" zeroes AFTER a nonzero digit but BEFORE an implicit or explicit decimal point are subject to the following conditions:

  • If an explicit decimal point is specified, they are significant if and only if a nonzero digit precedes them.
  • If no explicit decimal point is specified, they are NOT significant.

Therefore, there are TWO significant figures (not four).