Question

How many significant digits are in the number 5.40?

Answer 1

Three.

Explanation:

Terminal zeroes after the decimal point are not needed as placeholders; mathematically `5.40` has thebsame value as `5.4`. So including that extra zero is warranted only if the quantity is accurate enough to render that digit siginficant. That is, `5.40` is rendrered sufficiently accurate to diatinguish it from `5.39` and `5.41`, whereas without that level of accuracy we would have written just `5.4`.

Answer 2

Three.

Explanation:

Terminal zeroes after the decimal point are not needed as placeholders; mathematically `5.40` has thebsame value as `5.4`. So including that extra zero is warranted only if the quantity is accurate enough to render that digit siginficant. That is, `5.40` is rendrered sufficiently accurate to diatinguish it from `5.39` and `5.41`, whereas without that level of accuracy we would have written just `5.4`.