原式
=1÷(2÷3)÷(3÷4)÷(4÷5)÷(5÷6)
=1÷2×3÷3×4÷4×5÷5×6
=1÷2×(3÷3)×(4÷4)×(5÷5)×6
=1÷2×6
=0.5×6
=3