Przykład 1. Oblicz:

a) $\sqrt{225}=15$,  bo $15^2=225$

b) $\sqrt{20\frac{1}{4}}=\sqrt{\frac{81}{4}}=\frac{9}{2}$, bo ${\left(\frac{9}{2}\right)}^2=\frac{81}{4}$

c) $\sqrt{4,41}=2,1$, bo ${\left(2,1\right)}^2=4,41$

d) $\sqrt[3]{-27}=-3$, bo ${\left(-3\right)}^3=-27$

e) $\sqrt[3]{5\frac{23}{64}}=\sqrt[3]{\frac{343}{64}}=\frac{7}{4}=1\frac{3}{4}$, bo ${\left(\frac{7}{4}\right)}^3=\frac{343}{64}$