解，1.25x0.78x0.8=(1.25x0.8)x0.78=1x0.78=0.78
1.25×0.7×0.8=1.25×0.8×0.7=1×0.7=0.7利用乘法交换律和结合律计算乘法交换律a×b=b×a乘法结合律(a×b)×c=a×(b×c)
1.25×0.7×0.8=1.25×0.8×0.7=1×0.7=0.7。
1.25×0.8×0.7＝1×0.7＝0.7
