计算：;_+S7G/I0f7D/U-}.`
53×57-47×43;_+S7G/I0f7D/U-}.`
算式：提示2L:y5d3E3B;_+S7G/I0f7D/U-}.`
=6C.a9u7}8{-G-~;_+S7G/I0f7D/U-}.`