计算,能简算的要简算:(1)1÷4÷8÷0.25÷12.5 (2)9.75﹣5.42﹣(0.25+2.58)(3)8×2.7+6.2×1.4+3.5×8.6 (4)[+(20﹣4.7)×6]÷102.2.