Ответ:

  1. \(\sqrt{12}+\sqrt{27}=2\sqrt3+3\sqrt3=5\sqrt3\).
  2. \(\sqrt8+\sqrt{50}=2\sqrt2+5\sqrt2=7\sqrt2\).
  3. \(\sqrt{18}+\sqrt{200}=3\sqrt2+10\sqrt2=13\sqrt2\).
  4. \(\sqrt{300}-\sqrt{75}=10\sqrt3-5\sqrt3=5\sqrt3\).
  5. \(\sqrt{45}+\sqrt{500}=3\sqrt5+10\sqrt5=13\sqrt5\).
  6. \(\sqrt{48}-\sqrt{300}=4\sqrt3-10\sqrt3=-6\sqrt3\).
  7. \(\sqrt{80}+\sqrt{20}=4\sqrt5+2\sqrt5=6\sqrt5\).
  8. \(\sqrt{98}+\sqrt{72}=7\sqrt2+6\sqrt2=13\sqrt2\).
  9. \(-\sqrt{32}+\sqrt{50}=-4\sqrt2+5\sqrt2=\sqrt2\).
  10. \(\sqrt{90}-\sqrt{40}=3\sqrt{10}-2\sqrt{10}=\sqrt{10}\).
  11. \(\sqrt8+\sqrt2+\sqrt{32}=2\sqrt2+\sqrt2+4\sqrt2=7\sqrt2\).
  12. \(\sqrt{48}+\sqrt3-\sqrt{27}=4\sqrt3+\sqrt3-3\sqrt3=2\sqrt3\).
  13. \(\sqrt{20}+\sqrt{500}+\sqrt5=2\sqrt5+10\sqrt5+\sqrt5=13\sqrt5\).
  14. \(\sqrt{24}-\sqrt6-\sqrt{54}=2\sqrt6-\sqrt6-3\sqrt6=-2\sqrt6\).
  15. \(\sqrt{160}+\sqrt{10}-\sqrt{90}=4\sqrt{10}+\sqrt{10}-3\sqrt{10}=2\sqrt{10}\).
  16. \(\sqrt{200}+\sqrt{98}+\sqrt2=10\sqrt2+7\sqrt2+\sqrt2=18\sqrt2\).
  17. \(\sqrt3-\sqrt{300}+\sqrt{108}=\sqrt3-10\sqrt3+6\sqrt3=-3\sqrt3\).
  18. \(-\sqrt{12}+\sqrt3-\sqrt{75}=-2\sqrt3+\sqrt3-5\sqrt3=-6\sqrt3\).
  19. \(\sqrt2+\sqrt{242}+\sqrt{162}=\sqrt2+11\sqrt2+9\sqrt2=21\sqrt2\).
  20. \(\sqrt6+\sqrt{150}-\sqrt{600}=\sqrt6+5\sqrt6-10\sqrt6=-4\sqrt6\).