5.6×4.2+0.56×58脱式计算？解:原式=5.6×4.2+0.56×10×5.8=5.6×（4.2+5.8）=5.6×10=56运用乘法结合律计算
5.6X4.2+0.56X58=5.6X4.2+5.6X5.8=5.6X（4.2+5.8）=5.6X10=56
