15.52+7.8乘5减4.92脱式计算怎么写=15.52+39-4.92=15.52+40-（1+4.92）=55.52-5.92=55.52-6+0.08=49.6
脱式计算怎么写15.52+7.8×5-4.92=15.52+39-4.92=54.52-4.92=49.6
