A1/6
B4/7
C2/5
D2/3
Answer:
Related Questions:
11×2+12×3+13×4+14×5=\frac{1}{1\times2}+\frac{1}{2\times3}+\frac1{3\times4}+\frac1{4\times5}=1×21+2×31+3×41+4×51=
12÷23+1=\frac{1}{2} \div \frac{2}{3} + 1 = 21÷32+1= ______
