（1）3.2×0.25 （2）36×（5/9+1 /6） （3）1209－7236÷18 ( 4)4/5 × [(1/2+1/3)÷1/4]
=8 ×0.4 ×0.25 =36×5/9+36×1 /6 =1209-7236÷9÷2 =4/5 ×5/6 ×4
=8×0.1 =20+6 =1209-804÷2 =8/3
= 0.8 =26 =1209-402
=807