8.43×1/4+84.3×0.05+2.5×0.843 3.14平方+68.6×0.314

8.43×1/4+84.3×0.05+2.5×0.843
=8.43x0.25+8.43x0.5+8.43x0.25
=8.43x(0/25+0.5+0.25)
=8.43x1
=8.43
3.14平方+68.6×0.314
=3.14平方+6.86x3.14
=3.14x(3.14+6.86)
=3.14x10
=31.4