\[\boxed{\mathbf{534}.}\]
\[1)\ a = \sqrt{2} + \sqrt{3}\text{\ \ }и\ \ b = \sqrt{10};\]
\[Допустим,\ что\ верно:\]
\[\sqrt{2} + \sqrt{3} > \sqrt{10};\]
\[2 + 2\sqrt{2 \bullet 3} + 3 > 10;\]
\[5 + 2\sqrt{6} > 10;\]
\[2\sqrt{6} > 5;\]
\[4 \bullet 6 > 25;\]
\[24 > 25 - неверно.\]
\[Следовательно:\ \ \]
\[\sqrt{2} + \sqrt{3} < \sqrt{10}.\]
\[Ответ:\ \ a < b.\]
\[2)\ a = \sqrt{13} - \sqrt{12}\text{\ \ }и\ \ \]
\[b = \sqrt{12} - \sqrt{11};\]
\[Допустим,\ что\ верно:\]
\[\sqrt{13} - \sqrt{12} < \sqrt{12} - \sqrt{11};\]
\[\sqrt{13} + \sqrt{11} < 2\sqrt{12};\]
\[13 + 2\sqrt{13 \bullet 11} + 11 < 4 \bullet 12;\]
\[24 + 2\sqrt{143} < 48;\]
\[2\sqrt{143} < 24;\]
\[\sqrt{143} < 12;\]
\[143 < 144 - верно.\]
\[Ответ:\ \ a < b.\]