# How many significant digits does 520 have?

Sep 15, 2016

#### Explanation:

Right from the start, you should be able to look at this number and say that it has at least two significant figures given by the two non-zero digits it contains.

Non-zero digits are always significant, so look for them first when trying to figure out how many sig figs you have.

Now, let's focus on that zero.

A zero that follows all non-zero digits and is not followed by any non-zero digits is called a trailing zero. A trailing zero is significant when it follows a decimal point or when a decimal point directly follows it.

In your case, the zero in $520$ does not follow a decimal point, and no decimal point directly follows it, therefore it is not significant. You can thus say that the number $520$ has two sig figs.

Examples in which that zero would be significant

$52.0 \to$ the trailing zero follows a decimal point

$520. \to$ the trailing zero is followed directly by a decimal point