Question

计算：2-2^2-2^3-2^4-2^5-2^6-2^7+2^8=?求简便算法

Answer 1

假设

2-2^2-2^3-2^4-2^5-2^6-2^7+2^8=S

则

S/2=1-2-2^2-2^3-2^4-2^5-2^6+2^7

S+S/2=1+2^8=1+256=257

S=257*2/3=514/3