How many significant digits does the number 0.0034 have?

May 19, 2016

Two significant digits (3 and 4)

Explanation:

For zeros, the rule of significant digits can be tricky, but here are the general rules:

$1.$ Any zeros before any non-zero digit (which are all significant) are considered to be NON-significant. (The rule used in this example, 0.0034).

$2.$ Any zeros between any non-zero digits are SIGNIFICANT
$0.607$
In this case, there are three significant digits: 607

$3.$ Any zeros that are to the right of the decimal point and a non-zero number are SIGNIFICANT.
$6.000$
This number contains four significant digits (all the zeros are significant because they come after a non-zero digit and are after the decimal point).

And this notation is not seen as often, but I'll include it anyway:

$4$. If there is a bar above a zero, then that zero is considered significant.

$3 \overline{0} 0$
Since the first zero has a bar over it, then this number has two significant digits (the last zero is not a significant digit- there is no bar over it).