要使算式4×10＋20÷5按加法、乘法、除法的运算顺序进行计算，就要添0y7M4^0M5E0S，算式变为0B3n,s(W4s-~.K(r:F0Y3M3}8L-q+o。(\-M-]0T1?*~+s*X2y9d.s