66.6666÷12.5÷3.7÷0.8÷0.3
=(66.6666÷0.3)÷(12.5×0.8)÷3.7
=222.222÷10÷3.7
=222.222÷（10×3.7）
=222.222÷37
=(222+0.222)÷37
=222÷37+0.222÷37
=6+0.006
=6.006