Dễ thôi mà
\(\frac{25\times4-0,5\times40\times5\times0,2\times20\times0,25}{1+2+4+8+...+128+256}\)\(=\frac{100-\left(0,5\times20\right)\times\left(40\times0,25\right)\times\left(5\times0,2\right)}{1+2+4+8+...+128+256}\)
\(=\frac{100-10\times10\times1}{1+2+4+8+...+128+256}\)\(=\frac{100-100}{1+2+4+8+...+128+256}\)\(=\frac{0}{1+2+4+8+...+128+256}\)= 0
Chúc e học tốt!