# How many significant figures are in the measurement 0.0105 km?

##### 1 Answer

#### Explanation:

The first and most important thing to notice here is that your measurement contains **two non-zero digits**,

As you know, **all non-zero digits** are * significant*, so right from the start you know that your measurement contains

*at least*two significant figures

#0.0color(purple)(1)0color(purple)(5) -># two non-zero digits

Now, the zero that **precedes** the decimal point is **not significant** because it acts as a *placeholder zero* for a number that is **smaller than**

The same can be said for the zero that **follows** the decimal point. Once again, this zero is **not significant** because the number is **smaller than**

Finally, the zero that follows *sandwiched zero*, which basically means that it is being flanked by two **non-zero** digits.

**All** sandwiched zeroes are **significant**, which means that your measurement has a total of **three significant figures**, two non-zero digits and a sandwiched zero.

#color(red)(0).color(red)(0)color(purple)(1)color(darkgreen)(0)color(purple)(5) -># three sig figs