\(1.3^3+3^2-\left(2^7:2^5+7^8:7^7\right)\\ =27+9-\left(2^2+7\right)\\ =36-11\\ =25\)

22,2 tạ

B

\(13-18-\left(-42\right)-15\\ =13-18+42-15\\ =-5+42-15\\ =37-15=22\)

\(-\left(76+21\right)+\left(21-76\right)+10\\ =-97+\left(-55\right)+10\\ =-142\)

\(13-18-\left(-42\right)-15\\ =13-18+42-15\\ =22\)

\(A=2+2^2+2^3+...+2^{100}\\ A=\left(2+2^2\right)+\left(2^3+2^4\right)+...+\left(2^{99}+2^{100}\right)\\ A=\left(2+2^2\right)+2^2\left(2+2^2\right)+...+2^{98}\left(2+2^2\right)\\ A=\left(2+2^2\right)\left(1+2^2+...+2^{98}\right)\\ =6.\left(1+2+...+2^{98}\right)⋮3\\ \left(đpcm\right)\)