# How do you determine the number of significant figures if a number does not have a decimal place?

Jun 25, 2017

It's normally determined by the first and last non-zero digit, but can be otherwise indicated...

#### Explanation:

By default, the number of significant figures is the number of digits in the run from the first non-zero digit to the last.

For example:

$200340000$

has $5$ significant digits, namely "$20034$"

If you are given a number like $80000$, then by default it has just $1$ significant digit unless you are told otherwise.

One convention that is sometimes used is to indicate the last significant digit with an overbar or underbar, e.g.

$80 \overline{0} 00$

$80 \underline{0} 00$

These examples have $3$ significant figures, namely "$800$"