# How many significant digits does 520 have?

##### 1 Answer

#### Answer:

Two significant figures.

#### 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 **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 **two sig figs**.

Examples in which that zero would be significant

#52.0 -># the trailing zero follows a decimal point

#520. -># the trailing zero is followed directly by a decimal point