1) 2¹⁸ : (2⁷)²; 2) (7⁹)² : (7⁹)⁵; 3) 11⁵ · (11³)⁷ : 11²⁶; 4) 9² · 27; 5) (6¹² · (6³)⁵) / ((6⁵)⁴ · 6⁴); 6) (25⁴ · 125¹⁰) / 5³⁷.

1. \(2^{18}:(2^7)^2=2^{18}:2^{14}=2^4=16\).
2. \((7^9)^2:(7^9)^5=7^{18}:7^{45}=7^{-27}=\frac{1}{7^{27}}\).
3. \(11^5\cdot(11^3)^7:11^{26}=11^5\cdot11^{21}:11^{26}=11^{26}:11^{26}=1\).
4. \(9^2\cdot27=(3^2)^2\cdot3^3=3^4\cdot3^3=3^7=2187\).
5. \(\frac{6^{12}\cdot(6^3)^5}{(6^5)^4\cdot6^4}=\frac{6^{12+15}}{6^{20+4}}=6^{27-24}=6^3=216\).
6. \(\frac{25^4\cdot125^{10}}{5^{37}}=\frac{(5^2)^4\cdot(5^3)^{10}}{5^{37}}=5^{8+30-37}=5=5\).

Ответ: 1) 16; 2) \(\frac{1}{7^{27}}\); 3) 1; 4) 2187; 5) 216; 6) 5.