Par reāla skaitļa $a$ pakāpi ar naturālu kāpinātāju $n$ sauc reizinājumu, kurā skaitlis $a$ ņemts $n$ reizes.
$\begin{array}{l}{a}^{n}=\underset{⏟}{a\cdot a\cdot a\cdot ...\cdot a}\phantom{\rule{0.147em}{0ex}}\phantom{\rule{0.147em}{0ex}}\phantom{\rule{0.147em}{0ex}}\phantom{\rule{0.147em}{0ex}}\phantom{\rule{0.147em}{0ex}}\phantom{\rule{0.147em}{0ex}}\phantom{\rule{0.147em}{0ex}}\phantom{\rule{0.147em}{0ex}}\phantom{\rule{0.147em}{0ex}}\phantom{\rule{0.147em}{0ex}}\phantom{\rule{0.147em}{0ex}}\phantom{\rule{0.147em}{0ex}}\phantom{\rule{0.147em}{0ex}}\phantom{\rule{0.147em}{0ex}}{a}^{1}=a,\phantom{\rule{0.147em}{0ex}}\phantom{\rule{0.147em}{0ex}}\phantom{\rule{0.147em}{0ex}}\phantom{\rule{0.147em}{0ex}}{a}^{0}=1\phantom{\rule{0.147em}{0ex}}\left(\mathrm{ja}\phantom{\rule{0.147em}{0ex}}a\ne 0\right)\\ \phantom{\rule{0.147em}{0ex}}\phantom{\rule{0.147em}{0ex}}\phantom{\rule{0.147em}{0ex}}\phantom{\rule{0.147em}{0ex}}\phantom{\rule{0.147em}{0ex}}\phantom{\rule{0.147em}{0ex}}\phantom{\rule{0.147em}{0ex}}\phantom{\rule{0.147em}{0ex}}\phantom{\rule{0.147em}{0ex}}\phantom{\rule{0.147em}{0ex}}\phantom{\rule{0.147em}{0ex}}\phantom{\rule{0.147em}{0ex}}\phantom{\rule{0.147em}{0ex}}\phantom{\rule{0.147em}{0ex}}\phantom{\rule{0.147em}{0ex}}\phantom{\rule{0.147em}{0ex}}n\phantom{\rule{0.147em}{0ex}}\mathrm{reizes}\end{array}$
Piemērs:
$\begin{array}{l}{4}^{3}=4\cdot 4\cdot 4=64\\ {\left(-3\right)}^{4}=\left(-3\right)\left(-3\right)\left(-3\right)\left(-3\right)=81\end{array}$
$\begin{array}{ll}\mathit{bāze}\to & \begin{array}{l}\mathit{kāpinātājs}\\ {2}^{\begin{array}{l}↓\\ \phantom{\rule{0.294em}{0ex}}3\end{array}}=8\\ \begin{array}{l}↖↗\\ \mathit{pakāpe}\end{array}\end{array}\end{array}$

Ja negatīva skaitļa kāpinātājs ir pāra skaitlis, tad skaitļa pakāpe ir pozitīvs skaitlis.
Ja negatīva skaitļa kāpinātājs ir nepāra skaitlis, tad pakāpe ir negatīvs skaitlis.
Piemērs:
${\left(-2\right)}^{4}=16;\phantom{\rule{1.029em}{0ex}}{\left(-2\right)}^{3}=-8$
Ja kāpinātājs ir vesels negatīvs skaitlis:
${a}^{-n}=\frac{1}{{a}^{n}}$
Piemērs:
Pārveido par pakāpi!

$\begin{array}{l}\frac{1}{8}=\frac{1}{{2}^{3}}={2}^{-3}\\ \phantom{\rule{0.147em}{0ex}}\\ \frac{1}{{x}^{-4}}={x}^{4}\end{array}$