\(\sqrt{0} = 0\)

\(\sqrt{25} = 5\)

\(\sqrt{81} = 9\)

\(\sqrt{25} + \sqrt{16} = 5 + 4 = 9\)

\(10 \sqrt{121} + 12 \sqrt{9} = 10 ⋅ 11 + 12 ⋅ 3 = 146\)

\(\sqrt{16} ⋅ \sqrt{36} = 4 ⋅ 6 = 24\)

\((4 \sqrt{6})^{2} = 4^{2} ⋅ \sqrt{6}^{2} = 16 ⋅ 6 = 96 \text{.}\)

\((7 \sqrt{9} - 4) (7 \sqrt{9} + 4) = (7 \sqrt{9})^{2} - 4^{2} = 49 ⋅ 9 - 16 = 441 - 16 = 425 \text{.}\)

\((\sqrt{6})^{2} = 6 \text{.}\)

\(4 (\sqrt{6})^{2} = 4 ⋅ 6 = 24 \text{.}\)

\(3 \sqrt{15} - 10 \sqrt{15} = -7 \sqrt{15}\)

\(6 \sqrt{11} ⋅ 2 \sqrt{2} = 12 \sqrt{22}\)

\({\sqrt{30} \over \sqrt{3}} = \sqrt{10}\)

\({28 \sqrt{18} \over 7 \sqrt{6}} = {28 \over 7} ⋅ {\sqrt{18} \over \sqrt{6}} = 4 \sqrt{3}\)

\({21 \sqrt{90} \over 3 \sqrt{10}} = {21 \over 3} ⋅ {\sqrt{90} \over \sqrt{10}} = 7 ⋅ \sqrt{9} = 7 ⋅ 3 = 21\)