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计算: $\frac{1}{2}+\left(\frac{1}{4}+\frac{3}{4}\right)+\left(\frac{1}{6}+\frac{3}{6}+\frac{5}{6}\right)+\cdots+\left(\frac{1}{98}+\frac{3}{98}\right.$ $\left.+\cdots+\frac{97}{98}\right)=$
                        
不再提醒