Câu hỏi 5Tính $$\frac12+\frac24+\frac38+\frac4{16}+\cdots+\frac{10}{2^{10}}.$$ $\frac{509}{256}$$\frac{513}{256}$$\frac{356}{512}$$\frac{418}{512}$$\frac{47}{512}$