Det här är en översatt version av sidan Tiologaritm *Wordlist*. Översättningen är till 100% färdig och uppdaterad.

# Common Logarithms

A common logarithm is a logarithm which uses $10$ as its base. For example $\log_{10}(1000)$ is equal to $3$ because $10^3$ is equal to $1000.$

Log base-10 can be written $\log_{10}(),$ but since it is used so often, it has been shortened to $\lg().$ Most calculators use this base when you press the $\log$ button. For positive numbers of $a$, the definition of base-10 logarithm is as follows:

$a=10^b \quad \Leftrightarrow \quad b=\lg(a)$

The numbers $0.01, \, 0.1, \, 1, \, 10$ and $100$ can be written as powers of 10. In other words, $10^{\text{-} 2}, \, 10^{\text{-} 1}, \, 10^{0}, \, 10^{1}$ and $10^{2}$. If you calculate base-10 logarithms from these examples, you will see that they indicate the exponents of the powers of ten.

 $x$ $\lg(x)$ $=$ $0.01$ $0.1$ $1$ $10$ $100$ $\lg(0.01)$ $\lg(0.1)$ $\lg(1)$ $\lg(10)$ $\lg(100)$ $\text{-} 2$ $\text{-} 1$ $0$ $1$ $2$

You can also calculate common logarithms on a calculator.