\(\sqrt{1} = 1\)

\(\sqrt{9} = 3\)

\(\sqrt{64} = 8\)

\(\sqrt{64} - \sqrt{81} = 8 - 9 = -1\)

\(8 \sqrt{121} - 10 \sqrt{16} = 8 ⋅ 11 - 10 ⋅ 4 = 48\)

\(\sqrt{4} ⋅ \sqrt{9} = 2 ⋅ 3 = 6\)

\((7 \sqrt{2})^{2} = 7^{2} ⋅ \sqrt{2}^{2} = 49 ⋅ 2 = 98 \text{.}\)

\((5 \sqrt{7} - 2) (5 \sqrt{7} + 2) = (5 \sqrt{7})^{2} - 2^{2} = 25 ⋅ 7 - 4 = 175 - 4 = 171 \text{.}\)

\((\sqrt{11})^{2} = 11 \text{.}\)

\(3 (\sqrt{2})^{2} = 3 ⋅ 2 = 6 \text{.}\)

\(9 \sqrt{3} - 5 \sqrt{3} = 4 \sqrt{3}\)

\(2 \sqrt{2} ⋅ 6 \sqrt{17} = 12 \sqrt{34}\)

\({\sqrt{60} \over \sqrt{6}} = \sqrt{10}\)

\({12 \sqrt{70} \over 6 \sqrt{7}} = {12 \over 6} ⋅ {\sqrt{70} \over \sqrt{7}} = 2 \sqrt{10}\)

\({15 \sqrt{72} \over 5 \sqrt{8}} = {15 \over 5} ⋅ {\sqrt{72} \over \sqrt{8}} = 3 ⋅ \sqrt{9} = 3 ⋅ 3 = 9\)