# How many significant digits are in the number 5.40?

Jul 22, 2016

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 $5.4$.

Jul 22, 2016

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 $5.4$.